The lithium-rich layered oxide material is a kind of lithium ion battery cathode material,which has a solid solution structure. It exhibits a high reversible specific capacity exceeding 250 mAh/g, and its price is very cheap. It has been considered as the most promising candidate for the next generation of cathode material. However, the lithium-rich layered oxide cathode material is facing some problems such as high irreversible capacity loss in the first cycle, poor rate capability, as well as serious capacity fading and voltage decay, which hinder its commercial application. In this paper, the structure of lithium-rich layered oxides cathode material and its typical initial charge and discharge curve are introduced, and the mechanism of ion-doping, surface coating, and surface oxygen vacancy modification are mainly focused. Then, the reasons why different doping ions and coating materials applied to lithium-rich layered oxides cathode material have the different effects, and the advantages of co-doping and double coating are further analyzed. At last, considering the limitations of ion-doping, surface coated and surface oxygen vacancy modification during the modification of lithium-rich layered oxide cathode material, the joint mechanisms based on the above three modification methods are proposed, and a brief introduction of this joint mechanism is given.
Contents
1 Introduction
2 Structure and initial charge and discharge curve
3 Modification of lithium-rich layer material
3.1 Ion-doping
3.2 Surface coating
3.3 Surface oxygen vacancy modification
3.4 The joint mechanism
4 Outlook