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Application of Metal-Organic Frameworks-Derived Conversion-Type Anodes in Alkali Metal-Ion Batteries

Zhichao Liu , Hongliang Mu , Yan Li , Liu Feng , Dong Wang , Guangwu Wen

Progress in Chemistry ›› 2021, Vol. 33 ›› Issue (11) : 2002 -2023.

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Progress in Chemistry ›› 2021, Vol. 33 ›› Issue (11) : 2002-2023 DOI: 10.7536/PC200876
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Application of Metal-Organic Frameworks-Derived Conversion-Type Anodes in Alkali Metal-Ion Batteries
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Abstract

Alkali metal-ion batteries refer to secondary batteries with Li+, Na+, and K+ ions as carriers. They possess high energy density and long service life, and are widely applicated in electronic equipment and clean energy storage. Since the negative electrode plays a critical role on the electrochemical performance, it is urgent to develop high-performance negative electrode with high specific capacity and strong structural stability. It has been accepted that metal compounds anodes based on conversion-type mechanism feature with high theoretical specific capacity, good safety, and abundant resources. However, metal compounds suffer from poor electronic conductivity and obvious volume variation during charge/discharge processes, which damage the rate capabilities and cyclic performance. Using metal-organic frameworks(MOFs) as templates to fabricate metal compounds can effectively solve the above problems. MOFs-derived metal compounds possess distinct advantages when used as anodes for alkali metal-ion batteries:(1) abundant pore structures, which promote fast ion migration;(2) large specific surface area and enormous electrochemically active sites;(3) tunable structure and chemical composition. Herein, this review systematically combs the MOFs-derived conversion-type anodes and their applications in alkali metal-ion batteries. Firstly, three kinds of alkali metal-ion batteries are introduced briefly, and the research progress of various metal compounds derived from MOFs are reviewed. Then, the performance improvement strategies and mechanisms accompanied with MOFs-engaged strategy are summarized. At last, the advantages and challenges of the MOFs-derived conversion-type anodes in alkali metal-ion batteries are concluded, and the perspective of this research area is prospected.

Contents

1 Introduction

2 Alkali metal-ion batteries

2.1 Lithium-ion batteries

2.2 Sodium-ion batteries

2.3 Potassium-ion batteries

3 Metal compounds

3.1 Metal oxides

3.2 Metal sulfides

3.3 Metal selenides

3.4 Metal phosphides

3.5 Other metal compounds

4 Performance improvement strategies for MOFs-derived conversion-type anodes

4.1 Nanostructure engineering

4.2 Heterostructure engineering

4.3 Hybridization with carbon

5 Conclusion and outlook

Graphical abstract

Keywords

alkali metal-ion batteries / anodes / metal compounds / conversion-type materials / MOFs derivatives

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Zhichao Liu, Hongliang Mu, Yan Li, Liu Feng, Dong Wang, Guangwu Wen. Application of Metal-Organic Frameworks-Derived Conversion-Type Anodes in Alkali Metal-Ion Batteries. Progress in Chemistry, 2021, 33(11): 2002-2023 DOI:10.7536/PC200876

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1 Introduction

With the exploitation and consumption of fossil energy, the problem of energy and environment is becoming more and more serious. Green and clean energy is widely concerned by people, such as wind energy, tidal energy, solar energy and so on. However, these energy sources usually have regional, intermittent and other limitations, resulting in low energy efficiency. Therefore, the development of efficient and safe energy storage devices is the key to develop clean energy. A series of new energy storage devices have been developed, such as lithium-ion batteries, flow batteries, supercapacitors and so on. Alkali metal ion battery, represented by lithium ion battery, is a kind of energy storage device with high storage efficiency, pollution-free and reusable, which is considered to be an ideal carrier of clean energy in the future[1⇓~3].
Lithium-ion batteries (LIBs) are recyclable, green and efficient electrochemical secondary batteries with high energy density, high operating voltage, long service life and no memory effect, which are widely used in mobile phones, computers and other electronic devices[4,5]. With the rapid progress of science and technology, LIBs have also made great progress in the fields of electric vehicles, unmanned aerial vehicles and large power grids. However, the content of lithium (Li) resources in the earth's crust is only 0.0017%, which greatly limits the large-scale application of LIBs in the future energy society[6]. In order to solve this problem, sodium (Na) and potassium (K), which are in the same main group as Li, have come into view. Na and K have similar physical and chemical properties as Li, so sodium-ion batteries (SIBs) and potassium-ion batteries (PIBs) have the same working principle as LIBs. Importantly, Na and K are more abundant than Li, with Na content of about 2.83% and K content of about 2.09%, and they are more widely distributed globally. Therefore, the development of high-performance SIBs and PIBs is of great significance for the sustainable development of social energy[7,8]. However, the ionic radii of Li, Na, and K are gradually increasing (Li+ is 0.138 nm for 0.076 nm;Na+ and 0.102 nm;K+), which makes it more difficult for Na+ and K+ to be intercalated/deintercalated in the electrode material, and the volume change is more serious, resulting in electrode pulverization and capacity fading. Therefore, it is of great significance to design and develop new high-performance electrode materials, especially anode materials, for the practical application of alkali metal ion batteries[9⇓~11].
Anode materials are the key factors affecting the electrochemical performance of alkali metal ion batteries. According to the different reaction mechanisms with alkali metal ions, they can be divided into three types: intercalation type, alloy type and conversion type. The intercalation type negative electrode comprises graphite, soft carbon, hard carbon, porous carbon, graphene, titanium-based materials and the like, and the charge storage and release of the materials are realized through reversible intercalation/deintercalation of alkali metal ions in the internal space structure of the electrode[12,13][14,15][16,17][18,19][20,21][22,23]. Taking the graphite anode for LIBs as an example, the Li+ is intercalated into the graphite layers to form a lithium-graphite intercalation compound LiC6 during charging, and the Li+ is extracted from the graphite layers during discharging (6C+xLi++xe-↔LixC6). Although the intercalation anode has a stable structure and good electronic conductivity, its theoretical specific capacity is low, such as the theoretical lithium intercalation capacity of graphite anode is only 372 mAh·g-1.
The alloy anode, including Sb, Sn and other metals and P, Si and other non-metals, uses the alloying/dealloying reaction to achieve charge storage and release during the charge-discharge process[24][25][26][27]. Taking the silicon anode as an example, the Li+ forms a LixSi(0<x<4.4) with Si when it is embedded, and transforms into a Li+ and a Si(Si+xLi++xe-↔LixSi) when it is removed[28]. The biggest advantage of alloy-type anode is the high theoretical specific capacity, such as the theoretical specific capacity of P and Si materials applied to LIBs is 2596 and 4200 mAh·g-1, respectively. However, the alloy anode has a significant volume effect during charging and discharging (for example, the volume expansion of Si anode during lithium intercalation is as high as about 320%). The serious volume effect can lead to the rapid pulverization of the electrode, and then fall off from the current collector, and finally lose the electrochemical activity.
The conversion-type anode generally refers to various compounds of transition metal elements such as Fe, Co, Ni, Mn, Zn and the like, such as oxides, sulfides, selenides and the like. There is no space for alkali metal ions to be intercalated/deintercalated in the structure of these materials, but reversible redox reactions with ions occur, thus realizing charge storage and release. Taking the application of metal oxide Co3O4 in SIBs as an example, the reaction process can be expressed as a Co3O4+8Na++8e-→3Co+4Na2O. Because the whole electrochemical reaction process involves the participation of many electrons, the theoretical specific capacity (700~1200 mAh·g-1) of the conversion-type anode is usually much higher than that of the embedded-type anode[29]. In addition, although it also has a certain volume effect, it is often smaller than the alloy anode. Therefore, the conversion-type anode materials have great application potential in the field of alkali metal ion batteries. However, these materials also have inherent disadvantages: one is the volume effect, which will seriously damage the life of the battery, and this problem is more prominent in SIBs and PIBs; Second, the electronic conductivity is poor, which is easy to cause the degradation of electrode polarization and rate performance. Therefore, optimizing the structure and composition of conversion anode materials to improve their electron/ion transport characteristics and structural stability has become a hot research topic for researchers.
Metal-organic frameworks (MOFs) are a class of periodic network porous materials formed by the self-assembly of metal ions or metal clusters and organic ligands.MOFs have the advantages of adjustable pore structure, controllable chemical composition and large specific surface area, and are widely used in catalysis, gas separation, energy storage and other fields[30,31]. Benefiting from the controllable chemical composition and porous structural characteristics of MOFs, MOFs show unique advantages in the preparation of high-performance metal compounds and metal compound-based composites, which are mainly manifested in the following three aspects: (1) Metal compounds derived from MOFs.Generally, it can retain the regular pore structure and high specific surface area of MOFs, which can not only improve the active sites for charge storage, but also form a high-speed channel for ion transmission inside the electrode, making the insertion and extraction of ions more convenient. (2) High temperature treatment of MOFs materials in an inert environment can carbonize the internal organic components and form a compact carbon matrix in situ around the metal compounds, effectively buffering the volume change of the metal compounds in the process of ion deintercalation/intercalation, while accelerating electron conduction; (3) By adjusting the heat treatment process, the morphology and composition of the product can be precisely controlled, which is of great significance for the performance optimization of the conversion-type anode material.
In recent years, the preparation of metal compound-based electrode materials derived from MOFs has shown explosive growth, which has greatly promoted the development of alkali metal ion batteries. In this paper, the recent research progress in the preparation of conversion anodes using MOFs as precursors and their application in alkali metal ion batteries are reviewed. Firstly, the working mechanism of LIBs, SIBs and PIBs is briefly introduced.Then the MOFs-derived metal oxides, metal sulfides, metal selenides, metal phosphides and other conversion anode materials, as well as the accompanying performance optimization strategies are summarized. Finally, the development direction and prospects of this field are prospected.

2 Alkali metal ion battery

Alkali metals include lithium (Li), sodium (Na), potassium (K), rubidium (Rb), cesium (Cs), francium (Fr) and other elements, but only LIBs, SIBs and PIBs have been reported for alkali metal ion batteries. Therefore, this article will introduce the characteristics of LIBs, SIBs and PIBs, the working principle of charging and discharging batteries (Figure 1A), and the advantages of MOFs derivatives as conversion anode materials in LIBs, SIBs and PIBs.

2.1 Lithium-ion battery

The typical representative of alkali metal ion batteries is LIBs, which has attracted wide attention because of its high energy density, long service life, no memory effect and wide operating temperature range (-30 ~ 45 ℃)[72]. At present, the commercial LIBs mainly uses graphite as the negative electrode, the Li+ is released from the positive electrode during charging, moves in the electrolyte under the action of an electric field and is embedded between the graphite layers through a diaphragm, and the Li+ is released from the graphite layers during discharging and returns to the positive electrode through the electrolyte, thereby forming a complete charge-discharge cycle[73]. Graphite anode has good cycle stability and electronic conductivity, but its low theoretical specific capacity is the main factor limiting its further development. The conversion-type anode has a higher theoretical specific capacity and a suitable working potential (Figure 1b) than the graphite anode, which helps to improve the energy density and safety of the battery. The electrochemical reaction mechanism of the conversion-type anode when used in LIBs anode is shown in Formula 2.1:
${{\text{M}}_{a}}{{\text{X}}_{b}}+\left( b\text{*}c \right)\text{L}{{\text{i}}^{+}}+\left( b\text{*}c \right){{\text{e}}^{-}}\leftrightarrow a\text{M}+b\text{L}{{\text{i}}_{c}}\text{X}$
Wherein M represents a metal ion, and X represents elements such as O, S, Se, P and the like. Although the lithium storage capacity of the conversion-type anode can reach 700~1000 mAh·g-1, the large volume expansion and low electronic conductivity limit its high capacity. Therefore, the structural design and composition optimization of conversion-type anode materials are usually needed to improve electron transport and structural stability. The modification strategy based on MOFs has been proved to be an effective way. A wide variety of MOFs have been synthesized by selecting different metal ions and organic ligands. At present, the common MOFs used for the preparation of anode materials for alkali metal ion batteries mainly include ZIF-n (n = 8, 9, 67, etc.) Series, MIL-n (n = 53, 101, etc.) Series, HKYUST-1, MOF-n (N = 5, 74, etc) series, which can be pyrolyzed to obtain the corresponding metal compound-based anode[74]. By adjusting the morphology and structure of the MOFs precursor, hollow, porous, one-dimensional fibers and other nanostructured electrodes can be obtained, and the rich pore structure and high surface area can accelerate ion transport and increase active sites. For example, ZIF-67 was pyrolyzed and vulcanized to obtain CoS with hollow structure, which could maintain the specific capacity of 1668 mAh·g-1 after 100 cycles[75]. In addition, the carbon composite metal compound anode can be prepared by utilizing the characteristic that the organic ligand in the MOFs can be carbonized in situ after calcination in a protective atmosphere. In the composite electrode prepared by the in-situ carbonization of the MOFs, the carbon carrier and the metal compound have a strong coupling effect and a synergistic effect, so that the volume change of the electrode can be effectively relieved, the conductivity is increased, and the electrochemical performance is improved. He et al. Found that Fe-Mn-MOF was calcined in argon to obtain composite spheres composed of small particles, in which the small particles were composed of MnO doped in carbon-coated Fe3O4 and piled up in a layered structure[76]. The unique layered structure can improve the ion conduction rate and ease the volume change, while the synergistic effect between the in-situ grown carbon layer and the heterogeneous oxide can further increase the electronic conductivity at the interface, and the lithium storage capacity of the obtained electrode is still as high as 1297.5 mAh·g-1 after 200 cycles at 200 mA·g-1.

2.2 Sodium-ion battery

Na and Li belong to the same main group and have similar physical and chemical properties. Compared with Li, Na is more abundant in nature, and the development of SIBs can alleviate the growing shortage of Li resources. The working principle of SIBs is the same as that of LIBs, which is based on the reversible insertion/extraction of ions between positive and negative electrodes to achieve charge storage and release. SIBs is one of the ideal substitutes for LIBs and has great potential in the fields of large-scale static energy storage and low-speed electric vehicles. However, the ionic radius of V vs. SHE is 1.34 times larger than that of Li+, and the current graphite anode cannot meet the requirement of reversible intercalation/deintercalation of large-sized V vs. SHE. Moreover, the redox potential of V vs. SHE (− 2.71 V vs. SHE) is higher than that of Li+(-3.04 V vs.SHE), resulting in a slightly lower energy density of SIBs than LIBs. Therefore, it is of great significance to find anode materials with high capacity and good stability for the development of high-performance SIBs[77⇓~79]. The conversion-type anode based on the redox reaction has a higher theoretical specific capacity than the intercalation-type material (Figure 2C), and its sodium storage process is the same as LIBs, as shown in Equation 2.2:
${{\text{M}}_{a}}{{\text{X}}_{b}}+\left( b\text{*}c \right)\text{N}{{\text{a}}^{+}}+\left( b\text{*}c \right){{\text{e}}^{-}}\leftrightarrow a\text{M}+b\text{N}{{\text{a}}_{c}}\text{X}$
Wherein M represents a metal ion, and X represents elements such as O, S, Se, P and the like. Metal compounds used in the anode of SIBs are also limited by the large volume change and low conductivity during charge and discharge, and the ion transport is relatively slow due to the large ionic radius of Na+. It was found that MOFs derived metal compounds could inherit the pore structure of MOFs, and the pore size and distribution could be controlled by adjusting the calcination process, thus optimizing the diffusion of Na+ in the electrode. For example, Guo et al. Synthesized hollow MgFe2O4 microboxes using MgFe-PBA as precursor[80]. The porous hollow structure provides a high-speed transmission channel for the Na+ and relieves the internal stress generated in the process of sodium intercalation/deintercalation. It exhibits a high capacity of 406 mAh·g-1 at a current density of 50 mA·g-1. In addition, the calcination of MOFs in an inert atmosphere can carbonize the organic ligands in situ, which has a strong interfacial effect with metal compounds, can buffer the volume effect of the electrode, and accelerate the kinetics of sodium storage reaction. For example, Shuang et al. Synthesized a plate-like Ni-MOF using nickel nitrate as the metal source and terephthalic acid as the organic ligand[81]. In order to inhibit the aggregation of Ni3S2 particles and improve the conductivity, a layer of polypyrrole was grown on the surface of Ni-MOF, and the polypyrrole was transformed into a nitrogen-doped carbon layer after calcination, which also wrapped the Ni3S2 nanoparticles. The obtained Ni3S2@C has excellent sodium storage performance, and the reversible specific capacity is 432.8 mAh·g-1 after 100 cycles.

2.3 Potassium-ion battery

Potassium-ion batteries (PIBs), LIBs and SIBs have the same electrochemical reaction process, that is, electrochemical energy storage through the "rocking chair" charging and discharging mechanism. More importantly, PIBs also have the following advantages: first, the reserves of potassium are extremely abundant, and the crustal content is about 2.09%; Secondly, the redox potential of V vs. SHE (-2.93 V vs. SHE) is lower than that of Na/Na+(-2.71 V vs.SHE), and low electrode potential can effectively improve the energy density of the battery[82]. Furthermore, the Lewis acidity of K+ is the weakest, which can form smaller solvation ions, and the generated solvation energy can accelerate the migration rate of K+ in the electrolyte[83,84]. Although these advantages lay a favorable prospect for the development of PIBs, K+ has a larger ionic radius than Na+, which makes it more difficult to intercalate/deintercalate in the electrode, the reaction kinetics is poor, and repeated deintercalation of K+ will accelerate the cracking and pulverization of electrode materials, and ultimately damage the electrochemical performance of the battery[85]. Therefore, the development of PIBs urgently needs to develop electrode materials with high theoretical capacity, good conductivity and stable structure. Metal compounds have been shown to be a class of materials with excellent electrochemical potassium storage activity (fig. 2D), and their potassium storage process is shown in Equation 2.3:
${{\text{M}}_{a}}{{\text{X}}_{b}}+\left( b\text{*}c \right){{\text{K}}^{+}}+\left( b\text{*}c \right){{\text{e}}^{-}}\leftrightarrow a\text{M}+b{{\text{K}}_{c}}\text{X}$
Wherein M represents a metal ion, and X is an element such as O, S, Se, P and the like. Inspired by the high-performance LIBs and SIBs conversion anode derived from MOFs, the metal compound/carbon composite electrode was prepared by high temperature carbonization of MOFs materials, which also showed significantly improved performance when applied to PIBs anode. This is mainly due to the rich pore structure of MOFs materials, which is conducive to the rapid diffusion of K+ in the interior of the electrode, the in situ composite of carbon carriers can accelerate the electron transport, and the high surface area can provide abundant surface active sites, and finally the composite electrode has obvious pseudocapacitance characteristics and stable mechanical properties. In addition, metal ions with catalytic properties can be selected to synthesize MOFs, which are calcined in an inert atmosphere, and their organic ligands are catalyzed to graphitized carbon during carbonization, which has higher conductivity than amorphous carbon. For example, Miao et al. Used electrospinning technology to obtain nanofibers, then attached ZIF-67/ZIF-8 to them, and prepared composites with three-dimensional structure through multi-step calcination, in which CoP was embedded in carbon nanotubes grown on the surface of carbon nanofibers[86]. When applied to the PIBs anode, the reversible capacity was 247 mAh·g-1 after 1000 cycles at 0.8 A·g-1. This is due to the multiple protection of amorphous carbon, carbon nanotubes and carbon nanofibers on CoP. In the reaction process, carbon nanotubes and carbon nanofibers form an interconnected conductive network, resulting in synergy. In addition, researchers have prepared other types of metal compounds using MOFs as precursors, which also have excellent properties. For example, Yuan et al. synthesized Fe/Zn-MOF @ graphene oxide (RGO) from iron triacetylacetonate, zinc nitrate, phthalic acid, and RGO, and then selenized it at high temperature to obtain ZnSe-FeSe2@RGO composite[87]. Compared with ZnSe @ RGO or FeSe2@RGO, the ZnSe-FeSe2@RGO electrode showed much better cycling performance (the specific capacity after 100 cycles was 363 mAh·g-1. This is mainly attributed to the synergistic effect between the bimetallic component and its graphene, in which the ZnSe/FeSe2 heterojunction can provide high capacity, while the RGO can enhance the electrode conductivity and suppress the volume change, contributing to the improved rate capability and cycle life.

3 Metal compound

As mentioned above, MOFs are porous crystals formed by periodic arrangement of metal ions or metal clusters and organic ligands. By reasonably controlling the heat treatment process, the metal clusters of MOFs can be transformed into metal compounds in situ, while retaining the characteristics of high specific surface area and high porosity of MOFs. In recent years, more and more researchers have used MOFs as templates to prepare a variety of metal compounds, which have shown good electrochemical performance in the field of alkali metal ion batteries. In this part, this paper mainly summarizes the preparation of metal oxides, metal sulfides, metal selenides, metal phosphides and other compounds derived from MOFs and their applications in alkali metal ion batteries (Table 1).

3.1 Metal oxides

Metal oxides are the most typical conversion-type anode materials, which have been widely studied due to their wide variety, abundant resources and low cost. Metal oxides can be divided into two types according to different reaction processes with alkali metal ions. The first type is mainly transition metal oxides, which undergo oxidation-reduction reaction with ions in the charging process to generate a metal simple substance M YzO with the corresponding alkali metal oxide, the equation is as follows:[88]
${{\text{M}}_{a}}{{\text{O}}_{b}}+\left( b\text{*}z \right){{\text{Y}}^{+}}+\left( b\text{*}z \right){{\text{e}}^{-}}\leftrightarrow a\text{M}+b{{\text{Y}}_{z}}\text{O}$
Aft that oxidation-reduction reaction of the other oxide, the obtained metal simple substance continue to carry out alloying reaction with alkali metal ions to form a YnMa, wherein the reaction process is as follow:
$a\text{M}+n{{\text{Y}}^{+}}+n{{\text{e}}^{-}}\leftrightarrow {{\text{Y}}_{n}}{{\text{M}}_{a}}$
The metal oxides involved in this paper belong to the first category, which will produce obvious volume effect in the redox reaction, resulting in structural damage. In addition, the electronic and ionic conductivities of metal oxide anodes are poor, which limits the exertion of high capacity. It is found that metal oxides with porous structure and high surface area can be obtained by using MOFs as templates, which is conducive to accelerating ion transport and increasing active sites. For example, in the aspect of LIBs, Xu et al. prepared spindle-like Fe-MIL-88 from FeCl3·6H2O and 1,4-benzenedicarboxylic acid, and then obtained porous α-Fe2O3 assembled by nanoparticles by calcination in nitrogen and air, respectively. After 50 cycles, the specific capacity remained at 911 mAh·g-1, the rate capability was also excellent, and it still had a specific capacity of 400 mAh·g-1 at a high current density of 10 C (Figure 2a, B)[89]. Inspired by this, Li et al. Prepared Co-MOF from Co(NO3)2·6H2O and terephthalic acid, and then obtained Co3O4 with mesoporous structure by low temperature calcination[90]. The obtained Co3O4 has a large specific surface area, and its mesoporous structure is derived from the structure of the inherited Co-MOF, which shows stable cycling performance when used as LIBs anode. Although MOFs-derived metal oxides have abundant pore structures, which contribute to the rapid transport of ions, the electronic conductivity of monometallic oxides is still poor, and their electrode reaction kinetics still need to be further improved. Compared with the oxide with a single metal component, when the metal oxide with a bimetallic component is used as the negative electrode of a battery, a synergistic enhancement effect can be generated between different metal components, so that the reaction kinetics and the reaction activity of the electrode are remarkably improved, and the cycle life of the electrode is prolonged. Similar to the preparation of monometallic oxides, bimetallic oxides can be prepared by thermal treatment of bimetallic MOFs. Bimetallic MOFs materials can be obtained only by adding two metal salts in the liquid phase preparation process and combining them with organic ligands. Huang et al. Synthesized Zn-MOF with Zn(NO3)2·6H2O and 2-methylimidazole, and then mixed it with Co(NO3)2·6H2O to form Co-Zn-MOF by Co-precipitation.The bimetallic oxide ZnCo2O4 obtained by air calcination showed better lithium storage capacity than Co3O4, and the lithium storage capacity was 600 mAh·g-1 at the current density of 0.5 A·g-1[91]. In order to further improve the performance of the bimetallic oxide, a porous structure can be constructed inside the bimetallic oxide to shorten the ion diffusion path and improve the structural stability. Sambandam et al. Directly used Co-V-MOF as precursor to prepare Co3V2O8 porous microspheres by combustion method[92]. In the process of preparing Co-V-MOF, DMF was selected as the solvent, which could promote the rapid heat release of the solution during the heating process, so that the MOF material was decomposed and nucleated in the oxygen atmosphere, and finally the porous microspheres agglomerated by ultrafine particles with a particle size of about 20 ~ 50 nm were obtained, which had significantly improved cycle performance.
Importantly, calcining the MOFs precursor in a protective atmosphere can carbonize the organic ligands in situ to obtain carbon composite metal oxides, while retaining the pore structure of the precursor inside the electrode, which can not only promote electronic conduction and ionic conduction, but also effectively buffer the volume change of the oxide during charging and discharging, thereby improving the electrochemical performance. Zou et al. Synthesized hollow FeⅢ-MOF-5 octahedrons and then calcined them under nitrogen to obtain porous ZnO/ZnFe2O4/C octahedrons[93]. Upon calcination, FeⅢ-MOF-5 is decomposed into ZnO and ZnFe2O4 nanoparticles with a particle size of less than 5 nm, which are encapsulated in a three-dimensional carbon framework. The structure combines the multiple advantages of high specific surface, high porosity, hollow structure and carbon coating, and is beneficial to improving the cycle stability and rate performance of the electrode. The capacity after 100 cycles at 0.5 A·g-1 remained at 1390 mAh·g-1. It was found that the conductivity and electrochemical activity of carbon can be further improved by doping heterogeneous elements into the interior of carbon materials. Usually, organic ligands containing nitrogen, sulfur and other elements are selected to prepare MOFs precursors, and then carbon materials doped with heterogeneous elements can be obtained by high temperature calcination. For example, Denis et al. Obtained Ni-Co-MOF by hydrothermal method, then deposited Ni2+ and Co2+ on the uniform octahedron by KOH etching, and further heat treated to obtain NiCoO2 particles coated with nitrogen-doped carbon (Fig. 2C)[34]. Among them, trimesic acid was transformed into a porous, flexible, nitrogen-doped carbon framework, and the conductivity was significantly improved compared to the undoped carbon, while the nitrogen-doped carbon inhibited the agglomeration and expansion of NiCoO2 particles. The reversible lithium storage capacity of the obtained NC/NiCoO2 after 1000 cycles at 1.0 A·g-1 is 403 mAh·g-1.
In addition to the carbon materials obtained from the carbonization of MOFs themselves, foreign carbon sources, such as carbon nanofibers, graphene, carbon nanotubes, etc., can also be introduced during the preparation of materials[94][95][96]. Chen et al. Used polyacrylonitrile and cobalt acetate as raw materials to prepare nanofibers containing Co2+ by electrospinning technology, and then soaked them in 2-methylimidazole solution, so that ZIF-67 particles uniformly grew on the surface of the fibers, and finally obtained a multi-level composite structure of Co3O4 hollow spheres and carbon nanotubes through heat treatment[97]. The hollow Co3O4 and the tubular carbon fiber in the structure generate a synergistic effect, so that the volume expansion of the material is relieved; and meanwhile, the one-dimensional ultra-long carbon nanotube is beneficial to rapid migration of electrons, and has a 782 mAh·g-1 specific capacity at a 1.0 mA·g-1. In addition, metal oxides derived from MOFs can also be compounded with graphene, which can form a stable conductive skeleton around the oxide and improve the rate and cycle performance of the electrode by using the high electron mobility and high mechanical properties of graphene. For example, Gan et al. Used NiCo-BTC as precursor, formed needle-like structure through the regulation of graphene oxide, and then transformed into three-dimensional flower-like NiCo2O4/ graphene composites by calcination[98]. Graphene can not only control the morphology of materials, improve the specific surface area, but also greatly promote the electron transport. After 400 cycles, the obtained NiCo2O4/ graphene electrode still showed a high lithium storage capacity of 1067 mAh·g-1 at 1.0 A·g-1.
Metal oxides derived from MOFs can not only be used as LIBs anode, but also be widely used in SIBs. Zhang et al. Synthesized Cu-MOF with copper nitrate and trimesic acid as the main raw materials, and then calcined it at high temperature in protective atmosphere and air in turn, and finally prepared CuO/Cu2O hollow octahedron with porous structure[99]. The formation mechanism is that Cu-MOF decomposes into Cu/C composites at high temperature in protective atmosphere, and then oxidizes in air to decompose the internal carbon components, while Cu becomes CuO/Cu2O. The reversible capacity after 50 cycles is 415 mAh·g-1. In order to give full play to the sodium storage capacity of metal oxides and inhibit the volume effect of Na+ intercalation/deintercalation, it is also an effective strategy to composite metal oxides with carbon materials. Zhang et al. Prepared Mn-MOFs by co-precipitation method, and then calcined them under N2 atmosphere to prepare MnO/C nanorods, in which MnO nanocrystals were embedded in carbon materials[100]. The reversible sodium storage capacity of MnO/C nanorods at 50 mA·g-1 is 260 mAh·g-1. The introduction of external carbon source can also improve the sodium storage performance of metal oxides. For example, Li et al. prepared Cu-MOF @ graphene oxide by microwave irradiation, and then calcined it into CuO @ graphene at high temperature. After 50 cycles at 100 mA·g-1, the specific capacity was 466.6 mAh·g-1, which was superior to the reported CuO anode materials, mainly due to the three-dimensional conductive network formed by the highly conductive and ultra-thin graphene[101]. The above studies have mainly focused on monometallic oxides, which are still insufficient in their own conductivity. Similar to LIBs, MOFs-derived bimetallic oxides can also improve the electrochemical performance of materials. Zhang et al. added cobalt salt and nickel salt into the electrospinning solution to spin fiber fabrics, then added organic ligands to obtain Ni-Co-MOFs, and finally carbonized to obtain NiCo2O4/NiO/ carbon nanofibers[57]. It is found that the flexible carbon nanofibers provide sufficient buffer space for the volume growth of NiCo2O4/NiO during the charge-discharge process, and the synergistic effect among the multi-components can effectively improve the electron mobility and ion diffusion kinetics.
Metal oxide anode materials derived from MOFs have been widely used in alkali metal ion batteries. Reasonable design of metal oxides with special structures such as hollow structure, nanostructure and porous structure can promote the rapid diffusion of ions, and the structural stability can be further improved by carbon material composite. At present, the biggest challenge faced by metal oxides is the polarization problem caused by their own slow electron transport. The composite carbon material only accelerates the expansion of the electron transfer product on its surface, but its intrinsic conductivity still needs to be further improved. Therefore, improving the electrochemical reaction kinetics of metal oxides is one of the main research directions of MOFs derivation strategies in the future. Through the rational design of the chemical composition and spatial structure of MOFs precursors, the defect structure or heterostructure design of metal oxides is expected to enhance their electron transport characteristics and electrochemical activity.

3.2 Metal sulfides

Metal sulfide is another typical conversion-type anode, which is widely used in alkali metal ion batteries. Compared with oxides, metal sulfides have higher electronic conductivity and smaller volume expansion during ion insertion/extraction, thus showing higher structural stability and faster reaction kinetics[102,103]. Metal sulfides are divided into two groups according to their crystal structure. One is the layered structure (MS2(M are Mo, Sn, Ti, W, etc.), in which the MS2 are bound by weak Van der Waals force or intermolecular force, which is easy for reversible intercalation and deintercalation of alkali metal ions[104]. The other is non-layered sulfides, which are mainly obtained from ores, such as iron sulfide, cobalt sulfide, nickel sulfide, copper sulfide, etc. These materials involve multi-electron transfer during charging and discharging, and have higher working potential, so they have higher safety and theoretical capacity[105]. However, sulfide anode also has some disadvantages, taking LIBs as an example, when Li+ is embedded in metal sulfides, it will produce Li2Sx(2<x<8),Li2Sx which is very easy to dissolve in the electrolyte, resulting in the reduction of cycle performance. In addition, the volume effect of sulfide anode can not be ignored[106].
In the field of non-layered metal sulfides, researchers have successfully prepared a series of single-metal and multi-metal sulfides using MOFs as precursors, and applied them to alkali metal ion batteries, including Co1-xS/C, FeS@FeS2, NiS2/FeS2@NC, ZnCoS@Co9S8/NC, ZnCo2S4/NiCo2S4 and so on[107][33][108][109][110]. For example, Ma et al. used ZIF-67 as a precursor to form Co-C @ CNT by high temperature calcination, and then Co-calcined with sulfur powder to obtain CoS2-C@CNT composite[111]. The structure retains the high specific surface area of ZIF-67, and the Co nanoparticles calcined under protective atmosphere are uniformly embedded in the porous carbon, while catalyzing the conversion of carbon source into CNTs at high temperature (Fig. 3). Porous carbon and CNTs in the obtained product are mutually interwoven, so that the conductivity and the structural stability of the CoS2 are synergistically improved; and meanwhile, the abundant pore structure can provide a high-speed channel for ion diffusion, so that the CoS2-C/CNTs composite material has excellent lithium storage performance. The capacity retention is 80% after 500 cycles, which also shows good cycle performance when used as SIBs anode. In the above study, the prepared MOFs materials were reacted with sulfur powder at high temperature, which was prone to errors. In addition, sulfur-containing organic ligands can also be used to complex with metal ions in a liquid phase environment, which is helpful to precisely regulate the composition of the product. Dong et al. Synthesized Co-MOFs from cobalt nitrate and thiosemicarbazide, and then transformed them into NC/CoS2@Co4S3 microspheres by high temperature calcination[112]. By using the thiosemicarbazide as the sulfur source, the error caused by using sulfur powder as the sulfur source can be effectively avoided, and the obtained CoS2@Co4S3@NC has a fast electron/ion transmission channel and a significant pseudocapacitance behavior, and still has a high sodium storage capacity with a 200 mAh·g-1 under 6 A·g-1. However, the toxicity of cobalt itself limits the further application of cobalt sulfide. Among many metal sulfides, FeS2 is a promising anode material due to its low cost and non-toxicity. Yin et al. Calcined Fe-based MOFs as precursors to obtain porous carbon /Fe3O4 with octahedral structure, and further vulcanized to obtain FeS2/ porous carbon composite electrodes with concave structure[46]. The concave carbon framework integrates many advantages such as high stability, high ionic conduction and electronic conductivity, and the obtained FeS2/ porous carbon electrode can still maintain a high lithium storage capacity of 1074 mAh·g-1 after 100 cycles. With the development of MOFs, not only monometallic sulfides, but also a series of polymetallic sulfides, including bimetallic sulfides and trimetallic sulfids, have been successfully prepared by using MOFs derivation strategy. Polymetallic sulfides often exhibit more excellent electrochemical properties than monometallic sulfides. Wang et al. Used ZIF-67 as precursor, mixed CuSO4 with thioacetamide (TAA), and then carried out solvothermal reaction to prepare dodecahedral hollow CuCo2S4@C composites.The CuCo2S4 is composed of CuS4 tetrahedron and CoS6 octahedron, and exhibits a high reversible capacity of 1100.8 mAh·g-1 when applied to LIBs anode[113]. In order to make full use of the synergistic effect between metal components and give full play to the performance advantages of polymetallic sulfides, Cao et al. Sulfided Mn-Zn-Co-MOF and successfully prepared MnS- (ZnCo) S/NC. The synergistic effect between different metal components significantly improved the reaction kinetics of the electrode and maintained a stable sodium storage capacity of 353 mAh·g-1 after 400 cycles at 1 A·g-1[114]. In order to highlight the performance advantages of sulfides, the researchers also used the same precursor system to prepare Mn3O4-(ZnCo)O/NC, which had almost zero capacity after the same cycle.
At present, there are few MOFs materials assembled with Mo, Sn, Ti, W, Re and other metal ions, so there is very little work to directly transform MOFs into layered sulfides. However, porous carbon derived from MOFs can be used as a support to prepare layered metal sulfides and carbon composites by in-situ compounding or growth. For example, Lim et al. prepared porous carbon with high specific surface area (117.40 m2·g-1) and near micropores (2.20 nm) by carbonization and etching using Prussian blue as a precursor, and then grew ReS2 nanosheets on it in situ[115]. Ultrathin two-dimensional ReS2 nanosheets and porous carbon materials in ReS2@C can accommodate a large number of Na+ for rapid deintercalation, while improving the electron transport rate, and the presence of carbon carriers can also effectively alleviate the volume expansion of ReS2. Similarly, Hu et al. Mixed MIL-101 (Cr) with (NH4)2MoS4 and calcined them in Ar atmosphere to form a composite of MoS2 and chromium oxide, and finally etched off the chromium oxide with dilute sulfuric acid and potassium bromate to obtain uniform MoS2 nanocrystals supported on carbon materials[116]. The carbon materials derived from MOFs have strong binding force with two-dimensional MoS2, which effectively inhibits the growth and agglomeration of MoS2 nanocrystals, and the obtained composite electrode can provide a 870 mAh·g-1 specific capacity of potassium storage in the 100 mA·g-1. However, the use of dilute sulfuric acid makes the preparation process more complicated and the cost higher. Using ZIF-8 as a precursor to prepare the composite of MoS2 and carbon can avoid the use of acid. Shao et al. Heat treated ZIF-8 at high temperature to evaporate metal Zn and leave porous carbon, and then mixed the porous carbon with (NH4)2MoS4 and calcined it to form MoS2, which also showed excellent lithium storage performance[117].
Metal sulfides can be divided into non-layered and layered structures. Non-layered sulfides are rich in resources and can be obtained by direct heat treatment of the corresponding MOFs. Layered sulfides have attracted much attention due to their good mechanical stability, large interlayer spacing, thermodynamic stability and high electrical conductivity. Both layered and non-layered metal sulfides have high theoretical specific capacity, and the introduction of carbon materials helps to improve the conductivity and structural stability of sulfides, thus improving the electrochemical performance of materials. However, the transport of Na+ and K+ in sulfides is relatively slow. In addition, the discharge products are prone to "shuttle effect", resulting in slow reaction kinetics and capacity fading. How to rationally design the structure, composition and post-treatment process of MOFs precursors to make the derived metal sulfides have abundant hierarchical channels, high electronic conductivity and stable physical structure will be one of the main research directions of metal sulfides.

3.3 Metal selenide

Metal selenides, which have similar physical and chemical properties with sulfides, have also attracted much attention as conversion anodes. Compared with sulfur, selenium has a strong electronic conductivity (1×10-5S/m) and a weak electronegativity (2.5), so metal selenides have higher energy density and faster electrochemical reaction kinetics[118]. In addition, compared with oxides and sulfides, the bond strength of the metal-Se bond is relatively weak, which is conducive to the breaking of the bond and the occurrence of conversion reactions during charging and discharging. However, like other conversion anodes, metal selenides also have volume effect in the charge-discharge process, which leads to the decline of cycle performance. Using MOFs with high specific surface area and high porosity as templates to prepare metal selenides, the microstructure and chemical composition can be optimized to achieve high specific capacity and long cycle electrochemical performance[119,120].
There are generally two ways to prepare metal selenides using MOFs. One is directly obtained by one-step reaction after the MOFs and the selenium source are uniformly mixed. For example, Fan et al. Dispersed Ni-MOF and selenium powder in deionized water and KOH aqueous solution respectively, and then carried out hydrothermal reaction after uniform mixing to obtain NiSe2 with octahedral structure[121]. In the hydrothermal process, the reaction between the Ni-MOF and the selenium powder is more uniform in a liquid environment. The lithium storage capacity of the obtained NiSe2 octahedron after 500 cycles is 461 mAh·g-1. However, the electronic conductivity of pure metal selenides is poor, and the electrochemical performance needs to be further improved. In order to improve the conductivity, the precursor of MOFs can be selenized under protective atmosphere to obtain the corresponding carbon composite electrode. Yang et al. Synthesized Bi-MOF with 1,3,5-benzenetricarboxylic acid and bismuth nitrate as raw materials, and obtained the Bi2Se3 of porous carbon composite by in-situ selenization (Fig. 4)[122]. Porous carbon can not only stabilize the Bi2Se3 and inhibit its agglomeration, but also provide high-speed channels for ion diffusion and electron transfer. The obtained Bi2Se3@C exhibited excellent electrochemical performance in lithium/potassium ion batteries. In addition, metal selenides can also be compounded with nitrogen-doped carbon materials to improve their performance by utilizing the high electrochemical activity of nitrogen-doped carbon materials. Zhou et al. mixed Co-MOF, selenium powder and dicyandiamide, and then calcined them to prepare CoSe/Co @ NC composite material. Nitrogen-doped carbon with high conductivity and high electrochemical activity was compounded with metal selenide, which improved the conductivity of the whole electrode, thereby improving the charge storage capacity of the electrode[123]. However, after 500 cycles, the above materials still show obvious volume expansion, resulting in a downward trend in cycle performance. In order to further improve the cycle performance, the external carbon source can be introduced, and the structural stability of the electrode can be improved by using the synergistic enhancement of the external carbon source and the pyrolytic carbon. Yang et al. First compounded Co-MOF with CNTs to obtain pearl-like precursors, and obtained CNTs/CoSe2@NC composites after high temperature selenization[124]. The CNTs linked the dispersed CoSe2@NC particles together to form an interconnected conductive network, which enhanced the electron transport rate. When used in SIBs, the CNTs/CoSe2@NC retains a specific capacity of 404 mAh·g-1 after 120 cycles. While the capacity of CoSe2@NC without CNTs is only 83 mAh·g-1. In addition, bimetallic selenides can also be obtained by selenizing bimetallic MOFs in a protective atmosphere, and their in-situ composites with carbon materials can be realized. However, bimetallic selenides often exhibit more excellent electrochemical properties than monometallic selenides. For example, Wang et al. Prepared a composite of Fe-Mn-MOF and carbon nanotubes, and obtained Fe-Mn-Se/carbon nanotubes by selenization[125]. Wherein the Fe-Mn-Se spheres are assembled by finer nano particles, gaps are left between the nano particles to form a porous structure, and the porous Fe-Mn-Se nano spheres are further connected in series by carbon nano tubes to form a conductive network which is communicated with each other. Has 411 mAh·g-1 and high capacity when being used for the negative electrode of PIBs. In addition to carbon materials, components with high stability can also be introduced in the process of preparing metal selenides, and the synergistic effect between them can be used to improve the electrochemical performance of selenides. For example, Zhao et al. coated the surface of Co-MOF with TiO2, and then selenized it to prepare CoSe2@NC@TiO2 composites[126]. The TiO2 coating further enhances the stability of the structure, and the high sodium storage capacity of 374 mAh·g-1 can still be maintained after 200 cycles.
Another way is to calcine MOFs to obtain carbon-based composites, and then co-fire them with selenium powder to obtain metal selenide/carbon composites. For example, Li et al. First carbonized Co-MOF in nitrogen to prepare Co @ C composites, and then mixed and calcined with Se powder to obtain CoSe @ C, in which CoSe is uniformly distributed in the porous carbon matrix, effectively inhibiting the agglomeration and volume change of CoSe nanoparticles, while the carbon matrix can also accelerate electron transport[127]. As an anode material for SIBs, CoSe @ C maintains a reversible capacity of 341 mAh·g-1 after 100 cycles. Yang et al. carbonized Ni-Co-MOF at high temperature to obtain multilayer carbon-supported NiCo nanoparticles, and then selenized at high temperature to obtain hybrid structures of Ni3Se4/C and CoSe2/C[128]. It is found that the multi-stage carbon matrix can effectively inhibit the agglomeration and growth of particles during the first step of carbonization, and the structure does not change significantly after the second step of selenization, which is helpful to accelerate the electrode reaction kinetics and ensure the structural integrity. After 300 cycles, the obtained electrode maintains a 2061 mAh·g-1 lithium storage capacity, and the nanoparticles are still stably dispersed in the carbon matrix after many charge-discharge cycles.
The electrochemical activity of metal selenides is higher than that of oxides and sulfides, and their reaction kinetics is faster, usually showing excellent rate characteristics. However, the preparation process of metal selenides derived from MOFs reported at present is complex and the preparation cost is high, which limits their application. Moreover, the performance of selenides is generally low at high loading, which is mainly due to the inhibition of ion and electron transport when the electrode thickness increases, resulting in the decline of electrode reaction kinetics and low material utilization. Metal selenides are modified by the porous structure of MOFs, which can increase the active sites and improve the charge transport through the regulation of pore structure, thus improving the utilization of active materials. The three-dimensional network is constructed by further compounding high conductive materials such as nanofibers and carbon nanotubes, which is beneficial to improving the overall charge mobility. Therefore, the combined modification mechanism of MOFs structure regulation and three-dimensional conductive network design is expected to greatly improve the electrochemical performance of metal selenides at high loading in the future.

3.4 Metal phosphide

In recent years, metal phosphides have shown great potential as anodes for alkali metal ion batteries. Phosphorus is evenly distributed on the earth's crust, abundant in reserves and low in cost, and metal phosphides have low redox potential and high theoretical capacity (for example, FeP is 926 mAh·g-1;CoP and 894 mAh·g-1)[129]. However, the huge volume expansion of metal phosphides during electrochemical reaction will lead to the rapid pulverization of the structure, while the poor conductivity of phosphides itself limits the improvement of rate performance. Therefore, the design of metal phosphide electrode materials with fast electron/ion transport channels and stable spatial structure is one of the current research hotspots. MOFs have become an ideal precursor for the preparation of metal phosphides because of their rich pore structure, large specific surface area and uniform distribution of organic ligands. At present, researchers have prepared a series of metal phosphides including FeP, CoP, NiCoP and so on by using MOFs precursors[130][131][132]. One of the ways to improve the performance is to construct porous micro-nano structures to promote the full infiltration of electrolyte and rapid ion transport, while maintaining high mechanical properties. Li et al. added red phosphorus in the process of synthesizing Fe-MOF to obtain Fe-MOF @ P coated with red phosphorus particles, which was converted into FePx@P composite with rich pore structure after high temperature calcination, and the lithium storage capacity was 1283.9 mAh·g-1 after 80 cycles[32]. In addition, the carbon matrix obtained by high temperature carbonization of MOFs in a protective atmosphere can improve the electron transport of phosphides, alleviate the volume change during charge and discharge, and improve the electrode stability. Wang et al. obtained CoP/C nanoboxes by pyrolyzing the complex of phytic acid (PA) @ ZIF-67 (fig. 5)[133]. During the pyrolysis process, PA @ ZIF-67 evolved into a hollow nanobox, which increased the electrolyte/electrode contact area. In addition, the preparation of CoP/C nanoboxes with PA as the phosphorus source can reduce the composition error. The CoP/C nanocapsules exhibit ultra-high specific capacity and excellent cycling stability (523 mAh·g-1 after 1000 cycles at 500 mAh·g-1) when used as the negative electrode of LIBs. The introduction of foreign carbon sources can also further enhance the performance of MOFs-derived phosphides. For example, Ge et al. First modified nickel foam (NF) with polydiallyldimethylammonium chloride (PDDA) to make its surface positively charged, and then combined with GO through electrostatic attraction to obtain GO-NF, and then added GO-NF during the preparation of Co-MOF to make Co-MOF nucleate and grow uniformly on the surface of GO-NF, and finally obtained CoP @ C-RGO-NF-with core-shell structure, which showed excellent sodium storage capacity[134].
Similar to the aforementioned oxides and sulfides, in addition to single metal phosphides, double metal phosphides can also be prepared by using MOFs as a template, and the electrochemical activity and structural stability of the electrode can be improved by using the synergistic effect between different metal elements or different metal phosphides. For example, Duan et al. prepared NiCoP nanocages by etching ZIF-67 to precipitate Co2+ and co-precipitate with Ni2+ as NiCo-LDH nanosheets. As the reaction continued, the internal template disappeared and became a hollow structure. Finally, NiCoP nanocages were successfully prepared by phosphating with NaH2PO2[132]. The complete structure of the precursor was maintained after phosphating, and the sheets were cross-linked to each other to produce abundant porous channels, which provided rapid diffusion channels for ions. The NiCoP nanocages have a high lithium storage capacity of 622 mAh·g-1 after 100 cycles. However, the conductivity of metal phosphides is insufficient, and high conductivity components, such as carbon materials, are needed to make up for this defect. Li et al. Used iron-based Prussian blue (PB) as a template to grow Co(OH)2 in situ on its surface, forming a Co(OH)2@PB composite with cubic structure[135]. In order to form a high-speed conductive network inside the electrode, the Co(OH)2@PB was further functionalized by surface positive charges, and then combined with graphene oxide through electrostatic interaction, and finally phosphated by sodium hypophosphite to obtain the graphene coated RGO/CoP/C-FeP composite material with a hierarchical pore structure. The composite structure of the phosphide has a remarkable synergistic effect on components and a microstructure, and the abundant pore structure provides a passage for the rapid insertion/extraction of the Na+ and simultaneously relieves the stress caused by volume expansion,The heterointerface between CoP and FeP can provide additional active sites, while the tight binding of ultrathin graphene nanosheets with CoP/C-FeP particles provides a high-speed channel for charge transfer. When applied to SIBs anode, RGO/CoP/C-FeP still maintains 285 mAh·g-1 specific capacity after 200 cycles at 0.1 A·g-1.
Derivative strategies based on MOFs can improve the electrochemical performance of metal phosphides by modifying their porous structures and carbon composites. However, there are still some problems such as low capacity and unclear electrochemical reaction mechanism. By properly designing the structure of MOFs precursor and optimizing the heat treatment process, nanoscale metal phosphide and carbon composites can be prepared, which can increase the active sites of the materials and promote the electron/ion transport, thus improving the reaction kinetics and capacity. Aiming at the problem that the electrochemical mechanism of metal phosphides is not clear, the reaction mechanism of phosphides can be clearly clarified by observing the changes of structure and composition in the reaction process in real time with the help of in-situ spectroscopy and in-situ electron microscopy. The above results can help to guide the preparation process of MOFs derived strategy, so as to obtain metal phosphide anode materials with excellent performance.

3.5 Other metal compounds

In addition to the four types of conversion materials mentioned above, other types of metal compounds, such as metal carbides and nitrides, can also be derived from MOFs materials, which also have significant performance advantages and application potential as the anode of alkali metal ion batteries[136][137,138]. However, MoC usually requires high temperature preparation conditions, which will lead to serious agglomeration and growth of nanoparticles, thus reducing the active surface area of the material and not conducive to the rapid transfer of ions, so it is necessary to design a special structure to inhibit the agglomeration of MoC nanoparticles. However, Mo-based MOFs as a precursor, the in-situ carbon layer obtained by carbonization of organic ligands at high temperature can reduce the agglomeration and growth of MoC nanoparticles in the process of high temperature, and improve the active sites and electronic conductivity of MoC materials. Qi et al. Used trimesic acid and molybdenum hexacarbonyl to form Mo-MOF under high temperature magnetic stirring[139]. And then calcine in a protective atmosphere to prepare that garnet-shaped MoC @ C composite material. The pomegranate-shaped structure can reduce the consumption of electrolyte for the formation of the SEI film, and is beneficial to promoting the diffusion of Li+. At a current density of 200 mA·g-1, MoC @ C has a reversible capacity of 647.3 mAh·g-1. In order to further improve the electrochemical performance of carbide/carbon composite electrodes, heteroatom doping can also be used to improve the electronic conductivity and electrochemical reaction kinetics. Qiu et al. prepared Mo-MOF by using phosphomolybdic acid as the metal source and melamine as the organic ligand, and obtained hollow layered nitrogen-doped carbon composite MoC microspheres (NC/MoCxNy) after calcination in nitrogen atmosphere and Fe2+ etching[140]. In the nanostructure, the nitrogen-doped carbon matrix with a hollow structure can buffer the volume change of the MoCxNy nanoparticles, inhibit the aggregation of the nanoparticles, and alleviate the volume expansion of the nanoparticles in the process of insertion and extraction. In addition, in the first-principles calculation, the MoC,NC/MoCxNy shows a lower binding energy of Na+ adsorption than that of undoped nitrogen. After 200 cycles at the current density of 0.16 A·g-1, its specific capacity is 410 mAh·g-1, showing good cycling stability. However, the specific capacity of the above electrode is still low. It is found that the combination of metal compounds with different components to form heterostructures can regulate the charge transport at the interface and accelerate the electrode reaction kinetics. Yang et al. synthesized rod-like Mo3O10(C6H5NH3)2·2H2O precursor with (NH4)6Mo7O24·4H2O and aniline, and then calcined to prepare MoO2/Mo2C/C composite nanowires (Fig. 6)[141]. The unique nanowire structure shortens the path for Li+ transport, while the overall structure of the carbon-coated stabilizing material enables the material to have high specific capacity and cycle stability when used as LIBs anode, and the reversible capacity is 950 mAh·g-1 after 320 cycles.
Metal nitrides and carbides as negative electrode materials of alkali metal ion batteries have high theoretical specific capacity. Metal nitrides and carbides prepared with MOFs as precursors have high specific surface area, abundant pore structure, and in-situ carbon composite, which significantly improve their electrochemical activity and stability. However, compared with oxides and sulfides, metal nitrides and carbides have been less studied on the anode of alkali metal ion batteries, and their electrochemical reaction mechanisms are still unclear. Therefore, the synthesis of more types of metal nitrides and carbides based on MOFs and the study of their energy storage characteristics will be one of the hot research directions in the future.

4 Performance Improvement Strategy of MOFs Derived Conversion Anode

MOFs with periodic network structure, high porosity and tunable chemical composition provide an effective idea for the structural design and performance optimization of conversion materials, and the derivatives of MOFs can well inherit the structural characteristics of MOFs precursors during the conversion process. Firstly, the diversity and designability of MOFs lay a foundation for the construction of conversion materials with complex nanostructures, including low-dimensional nanostructures, hollow structures and porous structures. The unique micro-nano structures can endow electrode materials with high active surface area, fast ion diffusion channels and high mechanical properties. Secondly, the tunability of the chemical composition of MOFs is conducive to the preparation of heterostructured metal compounds, and the synergistic effect between different phases is conducive to accelerating ion transport and improving electrode reaction kinetics. Finally, the organic ligands of MOFs can be converted into carbon materials in situ, which can be closely combined around the metal compounds to improve the electronic conductivity of the whole electrode. In addition, MOFs materials can also be compounded with foreign carbon sources to construct composite electrodes with synergistic enhancement of multi-level carbon structures.

4.1 Nanostructure engineering

Nanostructure design is one of the most important ways to improve the electrochemical performance of conversion anodes, and it is also the most widely studied strategy. Nanostructured anode materials have large specific surface area, which can increase the active sites for charge storage and shorten the ion diffusion path, and accelerate the electrode reaction kinetics. In addition, the porous micro-nano structure can alleviate the internal stress caused by ion de-intercalation to a certain extent, and improve the stability of the electrode structure. However, aggregation usually occurs during the preparation of nanomaterials, which leads to the failure to fully utilize the active sites of the materials. The agglomeration problem of nanoparticles can be effectively solved by preparing nanostructured metal compounds with the characteristics of high porosity and controllable structure of MOFs materials. Therefore, nanostructured anodes derived from MOFs have broad development prospects in the field of alkali metal ion batteries.

4.1.1 One-dimensional nanostructures

The one-dimensional nanostructure comprises a nanowire, a nanorod, a nanofiber, a nanotube and the like, and the structure has a smaller radial dimension and a longer axial dimension, so that electrons can be transmitted more quickly in the axial direction, and ions can be embedded and removed more quickly in the radial direction, so that the rate capability of the material is improved. In addition, the one-dimensional nanostructure can also effectively alleviate the volume expansion generated during the charge-discharge cycle and improve the cycle stability of the electrode material. For example, Zhou et al. prepared one-dimensional rod-like structure Co-MOF by using Co(NO3)2·6H2O, 1,3,5-benzenetricarboxylic acid and 4,4 '-bipyridine as raw materials, and then prepared CoS/C nanorods by sulfurization[142]. The ultrafine CoS nanoparticles (average size about 7 nm) are embedded in the porous one-dimensional carbon nanorods, which can not only prevent the agglomeration of CoS particles, but also shorten the diffusion distance of Na+. The CoS/C nanorods have a specific capacity of 542 mAh·g-1 at 1 A·g-1 and maintain a high sodium storage capacity of 356 mAh·g-1 even at 4 A·g-1. Ma et al. Have vertically grown one-dimensional Co-MOF nanowire arrays on nickel foam, and then converted them into porous Co3O4 nanowires by high temperature calcination[143]. The one-dimensional nanowire structure provides abundant active sites for Li+storage and greatly shortens the diffusion path of ions during charging and discharging.
The work mentioned above is to directly prepare the precursors of MOFs with one-dimensional structure, and then convert them into metal compounds with one-dimensional structure. In addition, for MOFs materials which are difficult to synthesize one-dimensional structure, electrospinning technology can be combined with MOFs to weave MOFs composite materials with ultra-long one-dimensional structure, and then convert them into metal compound-based electrode materials with one-dimensional structure. For example, Zhang et al. First electrospun 2-methylimidazole and polyacrylonitrile (PAN) into nanofibers, and then grew polyhedral cobalt-zinc bimetallic MOFs on the nanofibers in situ[144]. Zn2+ are removed through high-temperature calcination to obtain Co-embedded nitrogen-doped carbon nanofibers, and then C/CoS2 nanoparticles grown on the nitrogen-doped carbon fibers are obtained through air oxidation and high-temperature vulcanization. The ultra-long carbon fibers are mutually interwoven to form a three-dimensional conductive network structure, which has dual effects on inhibiting the volume expansion of the CoS2 and improving the conductivity. When the obtained material is used as the negative electrode of SIBs, the specific capacity is 357 mAh·g-1 after 200 cycles. In addition, Chen et al. prepared ZIF-67 material in advance, and then directly spun it into ZIF-67/PAN composite material with nanofiber structure by adding it into the electrospinning solution. Finally, the composite material (Co3O4@NGFs) of Co3O4 composite nitrogen-doped graphitic carbon nanofibers was realized by two-step calcination, which showed excellent cycle stability for LIBs anode with a retention rate of 98.5% after 100 cycles[145]. Park et al. prepared porous carbon nanotube (CNT) microspheres through a one-pot spray pyrolysis process, and then coated uniform ZIF-67 on the surface to form a CNT/ZIF-67 composite, which was then calcined with selenium powder to obtain a nanorod CoSe2/NC composite (CoSe2@NC-NR/CNT) deposited on the surface of three-dimensional porous CNT microspheres (Fig. 7)[146]. When the porous structure is used as the electrode material of the SIBs, the intercalation and deintercalation of sodium ions are facilitated, and a three-dimensional conductive network is formed by the carbon nanotubes, so that convenience is provided for charge transfer, and the volume expansion of the CoSe2 is inhibited; and therefore, the discharge capacity can be 555 mAh·g-1 after 100 cycles.

4.1.2 Two-dimensional nanostructures

Two-dimensional (2D) nanosheet is a good anode material because of its high specific surface area and stable structure, which has three main application advantages: (1) large specific surface area is conducive to the penetration of electrolyte, shortens the ion diffusion path, and promotes the full utilization of the material; (2) the adjustable band gap is beneficial to electron conduction and effectively enhances the conductivity of the electrode; (3) The ultra-thin thickness makes the material have strong mechanical strength and flexibility, which can release the internal stress generated by the electrode material during charging and discharging. The preparation of metal compound nanosheets with two-dimensional structure using MOFs as precursors has unique advantages. During the preparation of MOFs, a precursor with a two-dimensional structure is formed under the action of a morphology directing agent, and then the precursor is calcined at a high temperature to decompose organic ligands to form two-dimensional nanosheets rich in holes. Li et al. Synthesized Co-MOFs nanoplates with cobalt acetate as metal source and 1,4-benzenedicarboxylic acid as organic ligand, and then obtained wrinkled porous Co3O4 nanosheets by air calcination[147]. In order to compare the morphology of nanosheets, bulk Co3O4 were also prepared as a comparison experiment. At the same current density and cycle number, the MOFs-derived porous Co3O4 nanosheets have more stable cycling performance and higher lithium storage capacity (1477 mAh·g-1) than the bulk Co3O4. Fang et al. Grown array-structured ZIF-67 on a three-dimensional conductive nickel foam substrate by liquid phase deposition, and then calcined it in air to decompose it into Co3O4 nanosheet arrays[148]. The Co3O4 nanosheet is composed of numerous tiny Co3O4 nanoparticles, the decomposition of organic components enables the surface of the Co3O4 nanosheet to be rich in abundant holes, and the porous nanosheet is tightly combined with the three-dimensional conductive foamed nickel, so that the porous nanosheet is a good binderless anode. When the current density is 0.5 A·g-1, the Co3O4 nanosheet electrode still has a lithium storage capacity of 1217 mAh·g-1 after 150 cycles, and 1204 mAh·g-1 remains even after 300 cycles, exhibiting excellent cycling performance.

4.1.3 Hollow Structure

The main advantage of the anode with hollow structure is its large specific surface area, which can greatly increase the active sites for ion storage, and the internal cavity structure can provide space for buffering the volume change of metal compounds and enhance the structural stability of the electrode. More importantly, MOFs are used as precursors to prepare metal compound materials with hollow structure, whose shell usually has abundant pore structure, which is very helpful for the electrolyte to fully infiltrate the whole electrode material, while greatly shortening the diffusion distance of ions[149,150]. For example, Zhang et al. Used Prussian blue as precursor to prepare hollow Fe2O3 with shell structure by slow heating in air[151]. In the process of high temperature calcination, Prussian blue is oxidized and decomposed with the growth of Fe2O3 crystals to form a hollow structure, which greatly increases the specific surface area of the electrode, and the large internal space also effectively releases the internal stress generated by volume expansion. As the negative electrode material of LIBs, the hollow Fe2O3 provided a specific capacity of 950 mAh·g-1 at 200 mA·g-1. Wu et al. Synthesized bimetallic ZnCo-MOFs with polyhedral structure using Co(NO3)2·6H2O, Zn(NO3)2·6H2O and 2-methylimidazole as raw materials, and finally converted them into ZnxCo3-xO4 polyhedrons with hollow structure after calcination in protective atmosphere, heat preservation in air atmosphere and cooling[152]. During the thermal decomposition process, the ZnxCo3-xO4 inherits the original porous structure of MOFs, while the slow decomposition of organic ligands leads to the formation of hollow structure inside, which makes the material have higher specific surface area and abundant electrochemical active surface, and shows significantly improved lithium storage capacity for LIBs anode.
Using MOFs as precursors, not only simple single-shell hollow structures can be synthesized, but also more complex hollow structures, such as core-shell structures and multi-shell structures, can be prepared. Compared with the simple hollow structure, the complex hollow structure has more obvious synergistic effect between the shell and the core. In addition, the inner shell can further increase the active sites of the material, thereby improving the utilization rate and volume energy density of the electrode. For example, Zhang et al. obtained core-shell Fe(OH)3 hexahedral structures with different layers by reacting Prussian blue with different concentrations of NaOH[153]. And then anneal in air to obtain that core-shell Fe2O3 hexahedron with different layer number (a to d in fig. 8). Under the same current density and cycle number, the multi-shell Fe2O3 has a higher specific capacity than the single-shell one. This is because the more the number of shells, the more active sites the entire electrode material can utilize, and thus the more capacity per unit mass it can provide. Similarly, Guo et al. Prepared NiCo-based bimetallic MOFs by surface ion exchange reaction, and obtained three-layer hollow CuO @ NiO composite material after calcination. LIBs test found that the multi-layer hollow structure could effectively alleviate the volume expansion caused by Li+ de-intercalation, showing excellent cycle performance[154]. By adjusting the heat treatment process of MOFs materials, metal compounds with core-shell structure can also be obtained. Compared with the hollow structure, the active material in the core-shell structure can participate in more electrochemical reactions. At the same time, the space can also alleviate the volume expansion and increase the contact area between the active material and the electrolyte. For example, Kong et al. Directly calcined Ni-based MOF under air to obtain NiO with micron-sized yolk-shell structure (Fig. 8e, f)[155]. It has a reversible capacity of 1060 mAh·g-1 at a current density of 0.2 A·g-1. In addition to the above control of the morphology and microstructure of the hollow structure, the control of its chemical composition can also be achieved, such as metal compound electrodes with different chemical compositions of shell and core. For example, Park et al. Etched ZIF-67 with Ni2+ to coprecipitate it with Co2+ to obtain a square core-shell structure, and finally reacted with selenium powder under Ar/H2 mixed atmosphere to obtain a composite electrode with a core-shell structure, in which the components of the core and shell are CoSe2 and (NiCo)Se2, respectively[156]. The double-layer hollow structure prepared by ion etching and calcination can fully contact with the electrolyte while increasing the surface area of the material and shorten the diffusion path of ions. The composite electrode still has a 661 mAh·g-1 sodium storage capacity after 80 cycles at 0.2 A·g-1.
It is found that the combination of various nanostructures is more conducive to improving the electrochemical performance of anode materials. For example, nanotubes combine the advantages of hollow structure and one-dimensional nanostructure, which can effectively alleviate the volume expansion of materials and increase the specific surface area of materials. Huang et al. First prepared iron-nickel bimetallic MOFs nanorods, then deposited Fe-MIL-88 on the surface, and finally calcined in air to form hollow nanotube NiFe2O4/Fe2O3 composites[157]. NiFe2O4/Fe2O3 hollow nanotubes are composed of nanoparticles with a diameter of about 78 nm. A reversible lithium storage specific capacity of 936.9 mAh·g-1 can be achieved at a current density of 100 mA·g-1. The high specific capacity of the structure is mainly due to the dual effects of the hollow structure and the nanorod structure. In addition, Xu et al. used Fe-MOF nanorods as precursors to wrap TiO2 on them by a simple chemical precipitation method, and then calcined the organic matter to decompose into CO2 and water, and the water vapor was volatilized to form a tubular structure, and finally sulfided to form a ternary FeS@TiO2@C nanotube material[158]. The hollow rod-shaped structure greatly increases the specific surface area of the material, so that the inner and outer surfaces of the material are fully contacted with the electrolyte, and the diffusion distance of sodium ions is greatly shortened. As a negative electrode material for SIBs, it retained a specific capacity of 444 mAh·g-1 after 150 cycles.

4.2 Heterostructure engineering

Integrating two or more phases of compounds to construct heterostructured composite electrodes is an effective way to improve the electrochemical performance of conversion-type anodes, and the unique coordination chemistry and tunable chemical composition of MOFs precursors provide an ideal template for the construction of heterostructured metal compounds. At present, researchers have prepared a series of heterostructured metal compound-based composite electrodes using MOFs as precursors, such as NC@Co3O4/Co, Cu2-xSe@CuO and so on, which show excellent performance in the field of alkali metal ion batteries[159][160]. In the heterostructure, the binding interface potential between different bandgap components is low, which can make electrons/ions pass through the surface interface of the electrode faster, thereby improving the electrochemical activity and reaction kinetics of the electrode, so it often shows higher specific capacity and cycle performance than single phase when it is used as the anode of alkali metal ion batteries. There are two methods to prepare heterostructured metal compounds by using MOFs as precursors. The first method is to add two or more different metal ions to co-precipitate with organic ligands when preparing MOFs, and then calcine the synthesized bimetallic MOFs materials to obtain heterostructured metal compounds or metal compound-based composites. For example, Sun et al. Prepared hollow Fe-Zn-MOF by microwave irradiation at high temperature under magnetic stirring, and then sulfurized to obtain sulfur-doped carbon-coated FeS2/ZnS hollow spheres (Fe-Zn-S @ S-C)[161]. FeS2 and ZnS exert a significant synergistic effect during cycling, facilitating electron transport and increasing reversible capacity. Compared to the single FeS2 or ZnS electrode, the heterostructured Fe-Zn-S electrode maintains a lithium storage capacity up to 1321 mAh·g-1 after 200 cycles. Zhang et al. synthesized a ZnSe@CoSe2/NC composite with a core-shell structure by calcining ZIF-8 @ ZIF-67 as a precursor with selenium powder at a ratio of 1:2 (Fig. 9)[162]. ZnSe and CoSe2 nanoparticles were in-situ grown in the core-shell N-doped carbon structure, which not only provided abundant active sites, but also shortened the diffusion rate of ions in the electrolyte.Meanwhile, the composite N-doped carbon further improved the conductivity of the material and the rate performance of the electrode. In addition, the heterostructure formed by the two components of ZnSe and CoSe2 also accelerates the electron migration rate. Compared with pure ZnSe/NC and CoSe2/NC materials, the reversible sodium storage capacity of ZnSe@CoSe2/NC anode is 499.1 mAh·g-1 after 100 cycles at a current density of 0.1 A·g-1. In addition, the electrode can still maintain a 273.5 mAh·g-1 reversible sodium storage capacity after 4000 cycles in 1.0 A·g-1. Wang et al. Prepared Cu-MOF while adding Ce(NO3)3·6H2O for co-precipitation, and then obtained CuO/Cu2O@CeO2 composites through N2 and calcination in air[163]. In the preparation process, the calcination process is skillfully designed to compound CuO with Cu2O to construct heterostructures with different compositions. Lattice distortion and charge redistribution are generated at the junction of the two components, which makes Na+ easier to adsorb and transfer, thereby increasing the reaction kinetics.The specific capacity of the obtained heterostructure electrode at 0.3 A·g-1 is 473 mAh·g-1.
The second method is to introduce foreign metal compounds again after the preparation of MOFs materials, which provides unlimited possibilities for the preparation of heterostructure metal compounds and greatly enriches the types of heterostructures. For example, Chen et al. First prepared MoO3 microrods by a simple thermal solvent method, and then deposited the obtained Co-MOFs on the surface of MoO3 microrods by soaking in cobalt nitrate and 2-methylimidazole solution[164]. And calcine with selenium powder in that mix atmosphere of Ar/H2 to generate the mesoporous layered MoSe2@CoSe/NC composite material. CoSe and nitrogen-doped carbon can be obtained in the composite structure by using Co-MOFs, and the MoSe2 and CoSe form a hybrid structure in the calcination process to generate a non-uniform interface, which is beneficial to improving the reaction kinetics and the ion transmission rate. Due to the synergistic effect between different components, the sodium storage capacity of MoSe2@CoSe/NC at a high current density of 2 A·g-1 is 398 mAh·g-1 after 300 cycles, and the capacity retention is 91.4%.

4.3 Carbon material composite

The common problem of conversion-type metal compound anode is the poor electronic conductivity, which leads to electrode polarization, and then affects the coulombic efficiency, reversible capacity and rate capability of the electrode, which greatly limits the practical application of conversion-type anode. In order to improve the electronic conductivity of the conversion-type anode, compounding it with highly conductive carbon materials is the most effective and commonly used means. In addition, as a flexible matrix phase, carbon materials also help to release the internal stress generated in the process of ion deintercalation and maintain the structural integrity and stability of the whole electrode. In recent years, a series of achievements have been made in the preparation of carbon composite metal compound-based composite anode materials using MOFs as precursors. According to the different compounding methods of carbon materials, the methods of preparing carbon-based composite electrodes derived from MOFs can be divided into two categories: (1) using the organic components of MOFs materials as carbon sources, carbonizing them in situ by high temperature heating to obtain carbon-based composite materials; And (2) additionally introduce other carbon sources in that preparation proces of the material, wherein the carbon sources comprise carbon materials such as graphene oxide, carbon nanotubes and the like, and polymer such as polyacrylonitrile, polypyrrole and the like which can be carbonized at high temperature.
In MOFs materials, metal ions are connected with organic ligands through coordination bonds to form a porous three-dimensional periodic structure, and the chemical bonds will be broken at high temperature, resulting in the precipitation of metal elements.At the same time, the organic ligand is carbonized in situ and retains the original pore structure, and finally a tightly combined and porous carbonaceous matrix is formed around the metal compound nanoparticles. The tightly bound carbon materials can accelerate the electron transport and collection, while the rich pore structure contributes to the rapid diffusion of ions, thereby improving the electrochemical performance of metal compounds. For example, Wang et al. synthesized bimetallic Zn-Mn-MOFs by coprecipitation using zinc acetate and manganese acetate as metal sources and trimesic acid as organic ligand, and obtained a special multilayer hollow disk-like structure by adjusting the content of added polyvinylpyrrolidone (PVP), and finally obtained a ZnxMnO@C composite material retaining the original morphology through high temperature calcination (Figure 10)[165]. In the structure, the ZnxMnO nanocrystals are tightly embedded into the inside of the porous carbon carrier, which is beneficial to releasing internal stress generated during charging and discharging, accelerating the transfer rate of electrons and improving the rate capability of the material. When used as the negative electrode of LIBs, the obtained composite electrode still has a reversible capacity of 853 mAh·g-1 after 500 cycles at 0.5 A·g-1. In addition, nitrogen doping can improve the electrochemical activity of carbon materials and improve the conductivity of electrodes, while nitrogen doping is usually used with porous carbon in MOFs self-derived carbon materials. For example, the organic ligand 2-methylimidazole has nitrogen-containing groups, and nitrogen-doped porous carbon materials can be obtained by calcination[166]. Similarly, Zhou et al prepared NC/ZnO composites by calcining ZIF-8 as precursor. In order to verify the effect of nitrogen on carbon structure, C/ZnO and pure ZnO were also prepared by using glucose as carbon source[167]. It is demonstrated that the ZIF-8 derived porous N-doped carbon framework can not only improve the electronic conductivity of ZnO, but also provide a high-speed diffusion channel for Li+ and inhibit the volume change during charging and discharging. Wang et al. Directly calcined ZIF-67 at high temperature to obtain nitrogen-doped carbon composite metal Co, and then sulfided it at high temperature to form CoS2@NC. When it was used as LIBs anode material, it still maintained 560 mAh·g-1 capacity after 50 cycles[168].
In addition to the carbon materials obtained from the carbonization of MOFs themselves, more and more researchers have focused on the external carbon source, which can further enhance the electrochemical performance of metal compound anodes by combining the synergistic enhancement of the external carbon source and the carbon matrix obtained from the carbonization of MOFs themselves. For example, Zhao et al. anchored Co2+ on graphene by electrostatic effect and then added organic ligands to form Co-MOF nanowires, and finally phosphated to obtain CoP @ NC/rGO composites with hierarchical micro/nanostructures[169]. The encapsulation of graphene not only greatly alleviates the volume change of CoP nanoparticles, but also reduces the agglomeration of particles, and increases the cycle stability and material utilization. The dual protection of graphene and MOF pyrolytic carbon enables CoP @ NC/rGO to achieve lithium storage capacities up to 733 mAh·g-1. In addition to direct composite carbon materials, MOFs precursors can also be compounded with polymers, and then double carbon composite metal compounds can be obtained by high temperature carbonization. For example, Atangana et al. prepared ZIF-67 @ PAN textile fibers by mixing cobalt nitrate, 2-methylimidazole, and PAN[170]. The Co0.85Se@CNFs is obtained by high-temperature calcination and selenylation, wherein the ultra-long carbon nanofibers are mutually interwoven to form a three-dimensional conductive network, which is beneficial to the rapid conduction of electrons; and the hollow structure of the Co0.85Se is coated in the carbon nanofibers, and the unique composite structure of hollow inside and coated outside can offset more stress generated by volume expansion. The Co0.85Se@CNFs nanocomposite still has a high reversible capacity of 353 mAh·g-1 after 100 cycles of deintercalation/intercalation of potassium ions. Zhang et al. prepared ZIF-8 and ZIF-67 by a simple liquid phase deposition method, and then coated them with a layer of PPy and calcined them at high temperature to decompose and carbonize PPy and organic ligands, and finally calcined them twice to obtain polygonal ZnO @ C and Co3O4@Cstructures[171]. The carbon-coated porous metal oxide produced by MOF derivation and PPy carbonization together forms a dual protection to inhibit volume change, so that the material has excellent conductivity and stable cycle performance. After 500 cycles at 250 mA·g-1, ZnO @ C and Co3O4@C achieved reversible lithium storage capacities of 526 and 721 mAh·g-1, respectively. To sum up, the composite material with external carbon source plays a good role in improving the performance, produces multiple advantages, improves the migration rate of electrons and ions, and improves the electrode reaction kinetics.

5 Conclusions and outlook

The conversion-type anode material based on the redox reaction has the advantages of higher theoretical capacity and lower volume effect than the intercalation-type anode material, and has great application potential in the field of alkali metal ion batteries. However, the development and application of conversion-type anode are still limited by the following two factors: one is the poor electronic conductivity, and the other is the volume effect during charge and discharge. This makes it difficult to give full play to the advantages of high specific capacity of conversion-type anode materials. MOFs are considered to be ideal precursors for the preparation of metal compounds due to their controllable pore structure, adjustable chemical composition and large specific surface area, which can optimize and regulate the physical structure and chemical composition of metal compounds. Therefore, this paper begins with a brief introduction of three kinds of alkali metal ion batteries (LIBs, SIBs and PIBs), and summarizes the preparation of metal oxides, sulfides, selenides, phosphides and other metal compounds derived from MOFs in recent years and their applications as negative electrodes of alkali metal ion batteries.In the end, the research progress in the preparation of metal compounds derived from MOFs by the strategies of low-dimensional nanostructures, hollow structures, heterostructures and carbon materials composite is reviewed, and the unique advantages of MOFs as a precursor for the preparation of metal compound electrode materials are systematically expounded.
Although great progress has been made in the preparation of conversion anodes derived from MOFs, there are still some problems that need to be solved urgently before the practical application of these materials. (1) The electronic conductivity of MOFs-derived conversion anode materials needs to be improved, which directly affects the rate capability and reversible capacity of the electrode. At present, the high transmission rate of charge and the improvement of electrode conductivity can be achieved by using carbon materials and composite foreign carbon sources transformed by MOFs themselves. (2) Conversion materials with special nanostructures can be controllably prepared by using MOFs as templates, including core-shell structures, multilayer hollow structures, one-dimensional nanostructures, etc. However, the mechanism of these nanostructured electrodes in the charge-discharge process remains to be further studied. By studying the relationship between different types of nanostructured electrodes and electrochemical performance, we can design the best nanostructure, and then obtain the best electrochemical performance. In situ electron microscopy and in situ electrochemical analysis can be used to observe the evolution of electrode composition and structure in real time, which provides strong technical support for the research in this field. (3) Metal oxides derived from MOFs generally inherit the original structure and morphology of MOFs precursors, but the structure and composition of materials will be greatly affected by the control of heating rate, cooling rate, holding time, calcination atmosphere and calcination temperature during calcination. Therefore, how to optimize the process parameters to achieve precise control of the structure and composition of metal compounds remains to be further studied. (4) The derivatives of multimetallic MOFs often show more excellent electrochemical properties than those of monometallic MOFs. However, the synergistic mechanism between different metal elements or different metal compounds is still unclear, which is very important for the optimization of performance and the structural design of metal compound electrodes. Theoretical calculations can provide strong theoretical support for the above studies, while in-situ spectroscopy can provide reasonable and credible data support for electrochemical mechanism studies. Although the above problems of MOFs-derived conversion anodes need to be solved, it is believed that with the development of advanced preparation and characterization technologies, the above problems can be effectively solved, which will ultimately promote the practical application of MOFs-derived conversion anodes in alkali metal ion batteries.

References

Publishing order | Descend order by publishing year | Descend order by cited within
[1]

Zhao R, Liang Z B, Zou R Q, Xu Q. Joule, 2018, 2(11): 2235.
[2]

Yap M H, Fow K L, Chen G Z. Green Energy Environ., 2017, 2(3): 218.
[3]

Cao B, Li X F. Acta Phys. Chimica Sin., 2020, 36(5): 89.
[4]

(曹斌, 李喜飞. 物理化学学报, 2020, 36(5): 89.)
[5]

Goodenough J B. Nat. Electron., 2018, 1(3): 204.
[6]

Zhong M, Kong L J, Li N, Liu Y Y, Zhu J, Bu X H. Coord. Chem. Rev., 2019, 388: 172.
[7]

Li X X, Zheng S S, Jin L, Li Y, Geng P B, Xue H G, Pang H, Xu Q. Adv. Energy Mater., 2018, 8(23): 1800716.
[8]

Li J H, Zhang J, Rui B L, Ling L, Chang L M, Nie P. Prog. Chem., 2019, 31(9): 1283.
[9]

(李佳慧, 张晶, 芮秉龙, 林丽, 常立民, 聂平. 化学进展, 2019, 31(9): 1283.)
[10]

Lei Y, Han D, Qin L, Zhai D Y, Kang F Y. Carbon, 2020, 159: 686.
[11]

Liang J M, Guo Y M, Wang M X, Hillidge , Zhang L J. Energy Storage Sci. Technol., 2019, 8(5): 813.
[12]

(梁菊梅, 郭雨萌, 王明暄, 希利德格, 张丽娟. 储能科学与技术, 2019, 8(5): 813.)
[13]

Zhao M T, Huang Y, Peng Y W, Huang Z Q, Ma Q L, Zhang H. Chem. Soc. Rev., 2018, 47(16): 6267.
[14]

Ma Y M. Energy Storage Sci. Technol., 2019, 8(3): 488
[15]

(马艳梅. 储能科学与技术, 2019, 8(3): 488.)
[16]

Kim J, Nithya Jeghan S M, Lee G. Microporous Mesoporous Mater., 2020, 305: 110325.
[17]

Tai Z X, Zhang Q, Liu Y J, Liu H K, Dou S X. Carbon, 2017, 123: 54.
[18]

Sun B, Zhang Q, Xiang H, Han F, Tang W, Yuan G M, Cong Y, Fan C L, Westwood A, Li X K. Energy Storage Mater., 2020, 24: 450.
[19]

Xie F, Xu Z, Jensen A C S, Au H, Lu Y X, Araullo-Peters V, Drew A J, Hu Y S, Titirici M M. Adv. Funct. Mater., 2019, 29(24): 1970164.
[20]

Xie X, Qi S H, Wu D X, Wang H P, Li F, Peng X X, Cai J F, Liang J J, Ma J M. Chin. Chem. Lett., 2020, 31(1): 223.
[21]

Liu C, Xiao N, Wang Y W, Li H Q, Wang G, Dong Q, Bai J P, Xiao J, Qiu J S. Fuel Process. Technol., 2018, 180: 173.
[22]

Zou G Q, Jia X N, Huang Z D, Li S M, Liao H X, Hou H S, Huang L P, Ji X B. Electrochimica Acta, 2016, 196: 413.
[23]

Li J P, Li Y J, Ma X D, Zhang K, Hu J H, Yang C H, Liu M. Chem. Eng. J., 2020, 384:123328.
[24]

Liu X, Zhang S C, Xing Y L, Wang S B, Yang P H, Li H L. New J. Chem., 2016, 40(11): 9679.
[25]

YongJian W U, RenHeng T, WenChao L I, Ying W, Ling H, Liu Zhang O. J. Alloy. Compd., 2020, 830.
[26]

Zhang X J, Wang M, Zhu G, Li D S, Yan D, Lu T, Pan L K. Ceram. Int., 2017, 43(2): 2398.
[27]

Zhong W, Tao M L, Tang W W, Gao W, Yang T T, Zhang Y Q, Zhan R M, Bao S J, Xu M W. Chem. Eng. J., 2019, 378: 122209.
[28]

Wang H, Wu X, Qi X J, Zhao W, Ju Z C. Mater. Res. Bull., 2018, 103: 32.
[29]

Wang H, Xing Z, Hu Z K, Zhang Y, Hu Y, Sun Y W, Ju Z C, Zhuang Q C. Appl. Mater. Today, 2019, 15: 58.
[30]

Tian W F, Wang L, Huo K F, He X M. J. Power Sources, 2019, 430: 60.
[31]

Chandra C, Kim J. Chem. Eng. J., 2018, 338: 126.
[32]

Luo F, Liu B N, Zheng J Y, Chu G, Zhong K F, Li H, Huang X J, Chen L Q. J. Electrochem. Soc., 2015, 162(14): A2509.
[33]

Wang Y, Wang C Y, Wang Y J, Liu H K, Huang Z G. J. Mater. Chem. A, 2016, 4(15): 5428.
[34]

Li T, Bai Y L, Wang Y, Xu H, Jin H. Coord. Chem. Rev., 2020, 410: 213221.
[35]

He H B, Li R, Yang Z H, Chai L Y, Jin L F, Alhassan S I, Ren L L, Wang H Y, Huang L. Catal. Today, 2021, 375: 10.
[36]

Li Z Q, Yin L W. Energy Storage Mater., 2018, 14: 367.
[37]

Wang H, Qian X K, Wu H Y, Zhang R H, Wu R B. Appl. Surf. Sci., 2019, 481: 33.
[38]

Denis D K, Wang Z L, Sun X, Zaman F U, Zhang J Y, Hou L R, Li J, Yuan C Z. ACS Appl. Mater. Interfaces, 2019, 11(35): 32052.
[39]

Zhong M, Yan J W, Wu H X, Shen W Z, Zhang J L, Yu C L, Li L, Hao Q E, Gao F, Tian Y F, Huang Y, Guo S W. Fuel Process. Technol., 2020, 198: 106241.
[40]

Wu Z R, Wang L P, Huang J, Zou J, Chen S L, Cheng H, Jiang C, Gao P, Niu X B. Electrochimica Acta, 2019, 306: 446.
[41]

Tian J J, Yang H, Fu C M, Sun M L, Wang L N, Liu T X. Compos. Commun., 2020, 17: 177.
[42]

Yuan D M, Cheng J L, Qu G X, Li X D, Ni W, Wang B, Liu H. J. Power Sources, 2016, 301: 131.
[43]

Wang W, Du Z R, Qian J C, Chen F. Mater. Lett., 2020, 259: 126827.
[44]

Batool S, Idrees M, Kong J, Zhang J X, Kong S F, Dong M Y, Hou H, Fan J C, Wei H G, Guo Z H. J. Alloys Compd., 2020, 832: 154644.
[45]

Wang F, Hu Z L, Mao L M, Mao J. J. Power Sources, 2020, 450: 227692.
[46]

Yang J, Zhang Y, Sun C C, Liu H Z, Li L Q, Si W L, Huang W, Yan Q Y, Dong X C. Nano Res., 2016, 9(3): 612.
[47]

Wang J M, Wang B B, Liu X J, Wang G, Wang H, Bai J T. J. Colloid Interface Sci., 2019, 538: 187.
[48]

Zhang W, Wang B, Luo H, Jin F, Ruan T T, Wang D L. J. Alloys Compd., 2019, 803: 664.
[49]

Gao C W, Jiang Z J, Wang P X, Jensen L R, Zhang Y F, Yue Y Z. Nano Energy, 2020, 74: 104868.
[50]

Yin W H, Li W Y, Wang K, Chai W W, Ye W K, Rui Y C, Tang B. Electrochimica Acta, 2019, 318: 673.
[51]

Han W W, Zhou Y, Zhu T, Chu H Q. Appl. Surf. Sci., 2020, 520: 146317.
[52]

Miao Y L, Zong J, Liu X J. Mater. Lett., 2017, 188: 355.
[53]

Chen Y M, Li X Y, Park K, Lu W, Wang C, Xue W J, Yang F, Zhou J, Suo L M, Lin T Q, Huang H T, Li J, Goodenough J B. Chem, 2017, 3(1): 152.
[54]

Wang Y, Li N, Hou C X, He B, Li J J, Dang F, Wang J, Fan Y Q. Ceram. Int., 2020, 46(7): 9119.
[55]

Zou G Q, Hou H S, Cao X Y, Ge P, Zhao G G, Yin D L, Ji X B. J. Mater. Chem. A, 2017, 5(45): 23550.
[56]

Jing W T, Zhang Y, Gu Y, Zhu Y F, Yang C C, Jiang Q. Matter, 2019, 1(3): 720.
[57]

Xu Y H, Zhu Y J, Liu Y H, Wang C S. Adv. Energy Mater., 2013, 3(1): 128.
[58]

Kim Y, Park Y, Choi A, Choi N S, Kim J, Lee J, Ryu J H, Oh S M, Lee K T. Adv. Mater., 2013, 25(22): 3010.
[59]

Liu S L, Zhang H Z, Xu L Q, Ma L B, Chen X X. J. Power Sources, 2016, 304: 346.
[60]

Li X W, Li S Y, Zhang Z X, Liu C Q, Qu B H, Pu J X. Mater. Lett., 2018, 220: 86.
[61]

Zhang W M, Cao P, Zhang Z H, Zhao Y J, Zhang Y, Li L, Yang K, Li X W, Gu L. Chem. Eng. J., 2019, 364: 123.
[62]

Li Z L, Zhao H L, Du Z H, Zhao L N, Wang J, Zhang Z J. J. Power Sources, 2020, 465: 228253.
[63]

Zhang W L, Zhou H H, Huang Z Y, Li S L, Wang C Q, Li H X, Yan Z H, Hou T, Kuang Y F. J. Energy Chem., 2020, 49: 307.
[64]

Liang J M, Zhang L J, XiLi D G, Kang J. Electrochimica Acta, 2020, 341: 136030.
[65]

Shi S S, Li Z, Shen L Y, Yin X P, Liu Y M, Chang G L, Wang J, Xu S M, Zhang J J, Zhao Y F. Energy Storage Mater., 2020, 29: 78.
[66]

Liu C, Xiao N, Li H J, Dong Q, Wang Y W, Li H Q, Wang S F, Zhang X Y, Qiu J S. Chem. Eng. J., 2020, 382: 121759.
[67]

Gao C L, Wang Q, Luo S H, Wang Z Y, Zhang Y H, Liu Y G, Hao A M, Guo R. J. Power Sources, 2019, 415: 165.
[68]

An Y L, Tian Y, Ci L J, Xiong S L, Feng J K, Qian Y T. ACS Nano, 2018, 12(12): 12932.
[69]

Fang K, Liu D, Xiang X Y, Zhu X X, Tang H L, Qu D Y, Xie Z Z, Li J S, Qu D Y. Nano Energy, 2020, 69: 104451.
[70]

Suo G Q, Zhang J Q, Li D, Yu Q Y, He M, Feng L, Hou X J, Yang Y L, Ye X H, Zhang L, Wang W. J. Colloid Interface Sci., 2020, 566: 427.
[71]

Han P Y, Zhao Y. Mater. Lett., 2020, 264: 127367.
[72]

Wang X J, Ma J Y, Wang J M, Li X F. J. Alloys Compd., 2020, 821: 153268.
[73]

Liu Y Z, Yang C H, Li Y P, Zheng F H, Li Y J, Deng Q, Zhong W T, Wang G, Liu T Z. Chem. Eng. J., 2020, 393: 124590.
[74]

Ma G Y, Li C J, Liu F, Majeed M K, Feng Z Y, Cui Y H, Yang J, Qian Y T. Mater. Today Energy, 2018, 10: 241.
[75]

Wang H H, Artemova A, Yang G, Wang H S, Zhang L L, Cao X, Arkhipova E, Liu J L, Huang Y Z, Lin J Y, Shen Z X. J. Power Sources, 2020, 466: 228303.
[76]

Sarma D D, Shukla A K. ACS Energy Lett., 2018, 3(11): 2841.
[77]

Liu X, Wu X Y, Chang B B, Wang K X. Energy Storage Mater., 2020, 30: 146.
[78]

Li Y, Zhang J W, Chen M H. Sustain. Mater. Techno., 2020, 26: e00217.
[79]

Wu R B, Wang D P, Rui X H, Liu B, Zhou K, Law A W K, Yan Q Y, Wei J, Chen Z. Adv. Mater., 2015, 27(19): 3038.
[80]

He Z S, Wang K, Zhu S S, Huang L A, Chen M M, Guo J F, Pei S E, Shao H B, Wang J M. ACS Appl. Mater. Interfaces, 2018, 10(13): 10974.
[81]

Wang Q, Chu S Y, Guo S H. Chinese Chem. Lett., 2020, 31(9):2167.
[82]

Wang Y, Liu Y K, Liu Y C, Shen Q Y, Chen C C, Qiu F Y, Li P, Jiao L F, Qu X H. J. Energy Chem., 2021, 54: 225.
[83]

Qi S H, Xu B L, Tiong V T, Hu J, Ma J M. Chem. Eng. J., 2020, 379: 122261.
[84]

Guo Y, Zhu Y Y, Yuan C, Wang C Y. Mater. Lett., 2017, 199: 101.
[85]

Shuang W, Huang H, Kong L J, Zhong M, Li A, Wang D H, Xu Y H, Bu X H. Nano Energy, 2019, 62: 154.
[86]

Li W T, An S L, Qiu X P. Energy Storage Sci. Technol., 2018, 7(3): 365.
[87]

(李文挺, 安胜利, 邱新平. 储能科学与技术, 2018, 7(3): 365.)
[88]

Xie J P, Li J L, Zhuo W C, Mai W J. Mater. Today Adv., 2020, 6: 100035.
[89]

Chen M Z, Wang E H, Liu Q N, Guo X D, Chen W H, Chou S L, Dou S X. Energy Storage Mater., 2019, 19: 163.
[90]

Fan S S, Liu H P, Liu Q, Ma C S, Yi T F. J. Materiomics, 2020, 6(2): 431.
[91]

Miao W F, Zhao X Y, Wang R, Liu Y Q, Li L, Zhang Z S, Zhang W M. J. Colloid Interface Sci., 2019, 556:432.
[92]

Yuan J J, Liu W, Zhang X K, Zhang Y H, Yang W T, Lai W D, Li X K, Zhang J J, Li X F. J. Power Sources, 2020, 455: 227937.
[93]

Wei G L, Jang Y, Zhou J H, Wang Z H, Hang Y X, Xie M, Wu F. Energy Storage Sci. Technol., 2020, 9(5):1318(in Chinese).
[94]

(位广玲, 江颖, 周佳辉, 王紫恒, 黄永鑫, 谢嫚, 吴锋. 储能科学与技术, 2020, 9(5):1318.)
[95]

Xu X D, Cao R G, Jeong S, Cho J. Nano Lett., 2012, 12(9): 4988.
[96]

Li C, Chen T Q, Xu W J, Lou X B, Pan L K, Chen Q, Hu B W. J. Mater. Chem. A, 2015, 3(10): 5585.
[97]

Huang J, Fang G Z, Liu K, Zhou J, Tang X K, Cai K N, Liang S Q. Chem. Eng. J., 2017, 322: 281.
[98]

Sambandam B, Soundharrajan V, Mathew V, Song J J, Kim S, Jo J, Tung D P, Kim S, Kim J. J. Mater. Chem. A, 2016, 4(38): 14605.
[99]

Zou F, Hu X L, Li Z, Qie L, Hu C C, Zeng R, Jiang Y, Huang Y H. Adv. Mater., 2014, 26(38): 6622.
[100]

Tolosa A, Fleischmann S, Grobelsek I, Presser V. ACS Appl. Energy Mater., 2018, 1(8): 3790.
[101]

Yan M Y, Wang F C, Han C H, Ma X Y, Xu X, An Q Y, Xu L, Niu C J, Zhao Y L, Tian X C, Hu P, Wu H G, Mai L Q. J. Am. Chem. Soc., 2013, 135(48): 18176.
[102]

Han B, Zhang W, Gao D, Zhou C G, Xia K S, Gao Q, Wu J P. J. Power Sources, 2020, 449: 227564.
[103]

Chen Y M, Yu L, Lou X W D. Angew. Chem. Int. Ed., 2016, 55(20): 5990.
[104]

Gan Q M, Liu B J, Zhao K M, He Z, Liu S Q. Electrochimica Acta, 2018, 279: 152.
[105]

Zhang X J, Qin W, Li D S, Yan D, Hu B W, Sun Z, Pan L K. Chem. Commun., 2015, 51(91): 16413.
[106]

Zhang X J, Zhu G, Yan D, Lu T, Pan L K. J. Alloys Compd., 2017, 710: 575.
[107]

Li D S, Yan D, Zhang X J, Li J B, Lu T, Pan L K. J. Colloid Interface Sci., 2017, 497: 350.
[108]

Zheng J, Xiong X H, Wang G H, Lin Z H, Ou X, Yang C H, Liu M L. Chem. Eng. J., 2018, 339: 78.
[109]

Li J F, Han L, Li Y Q, Li J L, Zhu G, Zhang X J, Lu T, Pan L K. Chem. Eng. J., 2020, 380: 122590.
[110]

Hu Z, Liu Q N, Chou S L, Dou S X. Adv. Mater., 2017, 29(48): 1700606.
[111]

Miao W F, Zhang Y, Li H T, Zhang Z H, Li L, Yu Z, Zhang W M. J. Mater. Chem. A, 2019, 7(10): 5504.
[112]

Ma Z T, Yao Z P, Cheng Y C, Zhang X Y, Guo B K, Lyu Y C, Wang P, Li Q Q, Wang H T, Nie A M, Aspuru-Guzik A. Nano Energy, 2020, 67: 104276.
[113]

Yang T, Yang D X, Liu Y G, Liu J, Chen Y F, Bao L, Lu X X, Xiong Q Q, Qin H Y, Ji Z G, Ling C D, Zheng R K. Electrochimica Acta, 2018, 290: 193.
[114]

Wang S D, Ning P, Huang S S, Wang W W, Fei S M, He Q Q, Zai J T, Jiang Y, Hu Z J, Qian X F, Chen Z W. J. Power Sources, 2019, 436: 226857.
[115]

Aslam M K, Shah S S A, Li S, Chen C G. J. Mater. Chem. A, 2018, 6(29): 14083.
[116]

Zhang H K, Liu J Y, Lin X R, Han T L, Cheng M Y, Long J W, Li J J. J. Alloys Compd., 2020, 817: 153293.
[117]

Ma Y, Ma Y J, Bresser D, Ji Y C, Geiger D, Kaiser U, Streb C, Varzi A, Passerini S. ACS Nano, 2018, 12(7): 7220.
[118]

Dong C F, Guo L J, Li H B, Zhang B, Gao X, Tian F, Qian Y T, Wang D B, Xu L Q. Energy Storage Mater., 2020, 25: 679.
[119]

Wang M H, Guo S P. J. Alloys Compd., 2020, 832: 154978.
[120]

Cao D W, Fan W D, Kang W P, Wang Y Y, Sun K A, Zhao J C, Xiao Z Y, Sun D F. Mater. Today Energy, 2019, 12: 53.
[121]

Lim Y V, Huang S Z, Wu Q Y, Zhang Y M, Kong D Z, Wang Y, Xu T T, Shi Y M, Ge Q, Ang L K, Yang H Y. Nano Energy, 2019, 61: 626.
[122]

Hu C, Ma K, Hu Y J, Chen A P, Saha P, Jiang H, Li C Z. Green Energy Environ., 2021, 6(1): 75.
[123]

Shao J, Gao T, Qu Q T, Shi Q, Zuo Z C, Zheng H H. J. Power Sources, 2016, 324: 1.
[124]

Wu C, Dou S X, Yu Y. Small, 2018, 14(22): 1703671.
[125]

Gao M R, Xu Y F, Jiang J, Yu S H. Chem. Soc. Rev., 2013, 42(7): 2986.
[126]

Shi Y F, Hua C X, Li B, Fang X P, Yao C H, Zhang Y C, Hu Y S, Wang Z X, Chen L Q, Zhao D Y, Stucky G D. Adv. Funct. Mater., 2013, 23(14): 1832.
[127]

Fan S W, Li G D, Yang G, Guo X, Niu X H. New J. Chem., 2019, 43(32): 12858.
[128]

Yang T, Liu J W, Yang D X, Mao Q N, Zhong J S, Yuan Y J, Li X Y, Zheng X, Ji Z G, Liu H, Wang G X, Zheng R K. ACS Appl. Energy Mater., 2020, 3(11): 11073.
[129]

Zhou Y, Tian R, Duan H N, Wang K F, Guo Y P, Li H, Liu H Z. J. Power Sources, 2018, 399: 223.
[130]

Yang S H, Park S K, Kang Y C. Chem. Eng. J., 2019, 370: 1008.
[131]

Wang J M, Wang B B, Liu X J, Bai J T, Wang H, Wang G. Chem. Eng. J., 2020, 382: 123050.
[132]

Zhao B, Liu Q Q, Wei G J, Wang J H, Yu X-Y, Li X, Wu H B. Chem. Eng. J., 2019, 378:122206.
[133]

Li J B, Yan D, Lu T, Yao Y F, Pan L K. Chem. Eng. J., 2017, 325: 14.
[134]

Yang T, Liu Y G, Yang D X, Deng B B, Huang Z H, Ling C D, Liu H, Wang G X, Guo Z P, Zheng R K. Energy Storage Mater., 2019, 17: 374.
[135]

Jiang H B, Chen B, Pan J M, Li C, Liu C Y, Liu L, Yang T, Li W, Li H H, Wang Y P, Chen L, Chen M. J. Alloy. Compd., 2017, 728: 328.
[136]

Han F, Zhang C Z, Yang J X, Ma G Z, He K J, Li X K. J. Mater. Chem. A, 2016, 4(33): 12781.
[137]

Li W J, Yang Q R, Chou S L, Wang J Z, Liu H K. J. Power Sources, 2015, 294: 627.
[138]

Duan J L, Zou Y L, Li Z Y, Long B. Powder Technol., 2019, 354: 834.
[139]

Wang X X, Na Z L, Yin D M, Wang C L, Wu Y M, Huang G, Wang L M. ACS Nano, 2018, 12(12): 12238.
[140]

Ge X L, Li Z Q, Yin L W. Nano Energy, 2017, 32: 117.
[141]

Li Z Q, Zhang L Y, Ge X L, Li C X, Dong S H, Wang C X, Yin L W. Nano Energy, 2017, 32: 494.
[142]

Zhao P P, Hua X, Xu W, Luo W, Chen S L, Cheng G Z. Catal. Sci. Technol., 2016, 6(16): 6365.
[143]

Xu Q H, Jiang H, Li Y H, Liang D, Hu Y J, Li C H. Appl. Catal. B-Environ., 2019, 256:117893.
[144]

Yoon K R, Shin K, Park J, Cho S H, Kim C, Jung J W, Cheong J Y, Byon H R, Lee H M, Kim I D. ACS Nano, 2018, 12(1): 128.
[145]

Qi J, Shi Z P, Li X, Gao B X, Wang H, Yang L C, Tang Y, Zhu M. J. Alloys Compd., 2019, 786: 284.
[146]

Qiu J, Yang Z X, Li Q, Li Y, Wu X, Qi C Y, Qiao Q D. J. Mater. Chem. A, 2016, 4(34): 13296.
[147]

Yang L C, Li X, Ouyang Y P, Gao Q S, Ouyang L Z, Hu R Z, Liu J, Zhu M. ACS Appl. Mater. Interfaces, 2016, 8(31): 19987.
[148]

Zhou L M, Zhang K, Sheng J Z, An Q Y, Tao Z L, Kang Y M, Chen J, Mai L Q. Nano Energy, 2017, 35: 281.
[149]

Ma Y Y, He J T, Kou Z K, Elshahawy A M, Hu Y T, Guan C, Li X, Wang J. Adv. Mater. Interfaces, 2018, 5(14): 1800222.
[150]

Zhang W M, Yue Z W, Wang Q M, Zeng X X, Fu C C, Li Q, Li X T, Fang L D, Li L. Chem. Eng. J., 2020, 380:122548.
[151]

Chen Y S, Wu T, Chen W Z, Zhang W H, Zhang L L, Zhu Z Y, Shao M, Zheng B, Li S, Zhang W N, Pei W B, Wu J S, Huo F W. Chem. Commun., 2020, 56(43): 5767.
[152]

Park S K, Kang Y C. ACS Appl. Mater. Interfaces, 2018, 10(20): 17203.
[153]

Li A, Zhong M, Shuang W, Wang C P, Liu J, Chang Z, Bu X H. Inorg. Chem. Front., 2018, 5(7): 1602.
[154]

Fang G Z, Zhou J, Liang C W, Pan A Q, Zhang C, Tang Y, Tan X P, Liu J, Liang S Q. Nano Energy, 2016, 26: 57.
[155]

Xu Z P, Huang Y, Chen C, Ding L de Zhu Y, Zhang Z, Guang Z X. Ceram. Int., 2020, 46(4): 4532.
[156]

Hu H, Zhang J T, Guan B Y, Lou X W D. Angew. Chem. Int. Ed., 2016, 55(33): 9514.
[157]

Zhang L, Wu H B, Madhavi S, Hng H H, Lou X W D. J. Am. Chem. Soc., 2012, 134(42): 17388.
[158]

Wu R B, Qian X K, Zhou K, Wei J, Lou J, Ajayan P M. ACS Nano, 2014, 8(6): 6297.
[159]

Zhang L, Wu H B, Lou X W D. J. Am. Chem. Soc., 2013, 135(29): 10664.
[160]

Guo W X, Sun W W, Wang Y. ACS Nano, 2015, 9(11): 11462.
[161]

Kong S F, Dai R L, Li H, Sun W W, Wang Y. ACS Sustainable Chem. Eng., 2015, 3(8): 1830.
[162]

Park S K, Kim J K, Kang Y C. J. Mater. Chem. A, 2017, 5(35): 18823.
[163]

Huang G, Zhang F F, Zhang L L, Du X C, Wang J W, Wang L M. J. Mater. Chem. A, 2014, 2(21): 8048.
[164]

Xu X J, Liu Z B, Ji S M, Wang Z S, Ni Z Y, Lv Y, Liu J W, Liu J. Chem. Eng. J., 2019, 359: 765.
[165]

Chen Z L, Wang S F, Zhang Z B, Zhou W L, Chen D J. Electrochimica Acta, 2018, 292: 575.
[166]

Zhang W X, Zhou Z Y, Zhao W R, Yang Z H, Yang X N. J. Mater. Chem. A, 2014, 2(16): 5800.
[167]

Sun W W, Tao X C, Du P P, Wang Y. Chem. Eng. J., 2019, 366: 622.
[168]

Zhang Z, Huang Y, Liu X D, Wang X, Liu P B. ACS Sustainable Chem. Eng., 2020, 8(22): 8381.
[169]

Wang L J, Wang X J, Meng Z H, Hou H J, Chen B K. J. Mater. Sci., 2017, 52(12): 7140.
[170]

Chen J, Pan A Q, Wang Y P, Cao X X, Zhang W C, Kong X Z, Su Q, Lin J D, Cao G Z, Liang S Q. Energy Storage Mater., 2019, 21: 97.
[171]

Wang D, Zhou W W, Zhang R, Huang X X, Zeng J J, Mao Y F, Ding C Y, Zhang J, Liu J P, Wen G W. J. Mater. Chem. A, 2018, 6(7): 2974.
[172]

Xu H F, Zhu G, Hao B M. J. Mater. Sci. Technol., 2019, 35: 100.
[173]

Zhou Z F, Zhang K, Liu J H, Peng H R, Li G C. J. Power Sources, 2015, 285: 406.
[174]

Wang Q F, Zou R Q, Xia W, Ma J, Qiu B, Mahmood A, Zhao R, Yang Y, Xia D G, Xu Q. Small, 2015, 11(21): 2511.
[175]

Zhao X J, Luo D, Wang Y, Liu Z H. Nano Res., 2019, 12(11): 2872.
[176]

Atangana E C, Huang H W, Hong H, Liu G X, Zhang L. Energy Storage Mater., 2020, 24: 167.
[177]

Zhang J, Chu R X, Chen Y L, Jiang H, Zeng Y B, Chen X, Zhang Y, Huang N M, Guo H. J. Alloys Compd., 2019, 797: 83.

Funding

Natural Science Foundation of Shandong Province(ZR2020QE066)

fellowship of China Postdoctoral Science Foundation(2020M672081)

Opening Project of State Key Laboratory of Advanced Technology for Float Glass(2020KF08)

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