Review on lithium-air batteries

Lithium-air battery has been a focus of study for the past two decades extensively because of its excellent properties of energy and power densities. The performance, operation mechanism and state-of-the-art of Li-air batteries, operated in all of electrolytes, such as non-aqueous electrolytes, aqueous electrolytes, ionic liquids electrolytes, aqueous-nonaqueous dual-electrolytes and all solid electrolytes, are collected and discussed in detail in this paper. In special, the performance, principle and potential practical possibility of lithium-air-super-capacitor battery, which was just mentioned last year, is also reviewed in detail. Combined with the electrochemical behavior and research results of oxygen reduction reaction on different electrodes in different non-aqueous electrolytes, the defect and problem of nonaqueous electrolyte lithium-air battery is also discussed. In this paper, the relationship between reversibility of ORR in organic electrolytes and rechargeable property of nonaqueous electrolyte lithium-air battery is discussed. In addition, some suggestions are exhibited based on relative research results. According to the device structure, electrochemical reaction of air electrode in different electrolytes and mass transfer behavior, the performances of organic-water dual-electrolyte lithium-air battery, all solid state electrolyte lithium-air battery and lithium-air-super-capacitor battery are compared and discussed. Moreover, some promising carbon-class electro-catalysts, such as graphene nanosheets(GNSs), are also exhibited for the development of Li-air batteries. At last, the performance and development of lithium-air batteries are summarized and some meaningful development directions, such as exploration of new electrolytes, electro-catalysts and design of novel structures, are suggested for the next generation of Li-air batteries.