Electrochemical power sources based on < anode ^metal | electrolyte | cathode ^oxygen > configuration have the highest energy density because the cathode active material(oxygen) is not stored in the battery, but can be accessed from the environment. Rechargeable lithium-air battery has been receiving more attention due to its high theoretical energy density of 5 210 Wh  ·g^-1, and it is considered as the next generation portable energy supply device for electronic vehicle(EV) and hybrid vehicle(HEV). This system has been understood by people in recent years. Although there are many unknown mechanisms in the electrochemical process of charge/discharge of the lithium-air battery, some achievements have been made on the development of oxygen reduction catalyst, air electrode materials and electrolyte materials. This paper reviews the achievements on lithium-air battery in the past few years from the respects of lithium-air battery system,cathode materials,electrolytes and lithium anode. The weaknesses are revealed and the future is prospected. Contents
1 Introduction
2 The main issues of lithium-air battery
3 Protection of lithium anode
4 Research on the electrolytes
4.1 Organic system electrolytes
4.2 Ionic liquid
4.3 Solid electrolyte
4.4 Aqueous electrolyte
5 Research on the air cathode
5.1 Porosity of air cathode
5.2 Efficiency of catalyst
6 Conclusions and perspective