Covalent S and Cl grafted porous carbon host realized via the one-step pyrolysis method results in boosted Li–O2 battery performances

Li–O 2 battery has attracted wide attention because it can satisfy the need for a new energy storage system with high energy density. However, poor oxygen reduction (ORR)/oxygen evolution (OER) kinetics involving Li 2 O 2 formation/decomposition is a major obstacle to its development. By designing suitable cathode with desired structure and surface electronic states, the formation/morphology of Li 2 O 2 and the reaction kinetics of charge process can be efficiently optimized simultaneously. In this work, a novel sulfur (S) and chlorine (Cl) co-doped porous carbon (CSC) were synthesized by one-step pyrolysis strategy, and the amount of heterogeneous atoms could be flexibly controlled by different calcination temperatures . Experimental combined with theoretical calculations show that the content of C Cl bond plays an important role in the adsorption of intermediate LiO 2 , thus regulating the morphology of Li 2 O 2 and ultimately affecting the release of battery energy. The C S bond mainly acts on the dynamics of the ORR and OER processes, which has an important influence on improving the round-trip efficiency of the battery. Benefiting from the synergistic effect of heteroatoms , the electrochemical performances of the Li–O 2 battery, including round-trip efficiency, discharge capacity and cycling stability are greatly improved.