Optimization of structural parameters of composite solid electrolytes to improve the safety and conductivity of lithium-air batteries

Lithium-air rechargeable batteries have attracted much attention because of their fairly large specific energy density. During this quarter century, three types of lithium-air batteries—namely nonaqueous, aqueous, and solid state have been proposed. The research efforts have been concentrated on the nonaqueous system because it is simpler compared with the aqueous system and is expected to develop a battery with a higher energy and power density than the solid-state system. However, decomposition of the electrolyte in nonaqueous systems by the reaction products is a challenging problem to commercialization. The solid systems are considered to be stable for the reaction of the electrolyte with the reaction products and safer than the nonaqueous system with a flammable electrolyte. In this review we introduce the present perspective on solid-state lithium-air rechargeable batteries. There are significant differences between the discharge mechanisms in Li-O2 batteries based on liquid electrolyte and solid state batteries that have been reported recently. Non-aqueous electrolytes cause problems such as the flammability of organic materials; Therefore, the importance of solid electrolytes becomes more apparent Recently, a new ceramic-polymer electrolyte has been reported to have high ionic conductivity and mechanical stability, as well as excellent compatibility and chemical stability at the interfaces of a lithium-air battery.