Recent progress in cathode materials and structures for Nonaqueous lithium–oxygen batteries

energy technologies are needed to resolve current issues of energy production including environmental degradation, raw material shortages and increasing energy demand. Metal-air batteries, especially aprotic Li-O2 batteries, offer an alternative which have higher theoretical energy density (≈3600 Whkg−1) and are more environmentally-friendly when compared to widely used Li-ion batteries.[1] these batteries still suffer from many critical issues, such as low capacity, poor cycle life, and low round-trip efficiency, rendering the practical application of these batteries rather sluggish. Cathode catalysts with high oxygen reduction reaction (ORR) and evolution reaction (OER) activities are of particular importance for addressing these issues and consequently promoting the application of Li–O2 batteries. To handle the above problems, many researchers have been endeavoring to develop efficient ORR and OER electrocatalysts to improve the performance of Li-O2 batteries. In the last decade, numerous ORR and OER catalysts emerged. Overall, the catalysts include porous carbon materials [2], transition metal oxides [3] and nitrides [4], precious metals [5], and perovskite- or pyrochlore-based compounds [6]. This paper reviews, the role of the cathode in nonaqueous Li–air batteries including the cathode reaction mechanisms and the properties and morphologies of cathode materials in recent advancements of these batteries.