Cathode electrocatalyst in aprotic lithium oxygen (Li-O2) battery: A literature survey

Lithium oxygen battery (LOB) is a highly promising energy storage device for the next generation electric vehicles due to its high theoretical energy density. However, many challenges hinder its practical application. The electrochemical performances, such as discharge capacity, discharge and charge overpotentials, power density and stability are all far from satisfactory. In recent years, a great progress has been made and numerous works on cathode materials have been published. This article focuses on the state-of-the-art of LOB cathode materials and the reaction mechanism happens on the cathode. The principles of cathode reactions are summarized and the requirements for cathode materials are discussed. The performance of LOBs with carbon-based and carbon free cathode materials are described. The approaches on improving the cathode performance via temperature increase, material surface engineering, texture optimization and oxygen vacancy regulation are elaborated. A perspective on the research trend on the cathode catalyst is finally proposed.