A COMPOSITE OF CO3O4 HOLLOW NANOPARTICLES AND CO ORGANIC COMPLEXES HIGHLY DISPERSED ON N-DOPED GRAPHENE AS CATHODE CATALYST FOR RECHARGEABLE LI-O2 BATTERIES

摘要

Rechargeable Li-O2 batteries have been considered as the mostnpromising system to satisfy the demand of electric vehicles,1 sincenthe availability of an unlimited source of oxygen from ambient airnmakes it more attractive as next-generation energy storage devices.2nParticularly, Li-O2 batteries exert a superior theoretical specificnenergy of nearly 11680 Wh/kg, which is close to the value ofngasoline (13000 Wh/kg).3-6 However, before practical applications,nmany fundamental problems need to be solved for Li-O2 batteries,nincluding low round-trip efficiency, poor rate performance, and shortncycle life in electrochemical processes.7-9 In order to solve thesenproblems, adding efficient cathode catalysts could drasticallynpromote the electrochemical performance. Until now, intensivenefforts have been devoted to explore cathode catalysts, includingnporous carbon materials,10 transitional metal oxides,11 and somenprecious metals.12 In this work, we present a hydrothermalcalcinationnmethod to prepare a composite of Co3O4 hollownnanoparticles and Co organic complexes highly dispersed on Ndopedngraphene (Co-NG), which acted as a bifunctional air cathodencatalyst to optimize the electrochemical performances of Li-O2nbatteries.