MODULATION OF OXYGEN REDUCTION REACTION FOR STABLE LITHIUM-OXYGEN BATTERIES

Abstract

Lithium oxygen batteries have attracted extensive attention due to its exceptionally high energy density. However, the high overpotential resulted from insulating discharge product and poor high-rate performance greatly restrains the actual performance. Herein, we aimed at promoting ORR kinetics of lithium oxygen batteries to improve the conductivity of discharge product and enhance the stability especially at large current densities. Firstly, Rh/rGO was employed as cathode material. Stabilized LiO2 due to high ORR catalytic activity and template effect led to the reduced charge overpotential and long cycle life. Then high oxygen pressure environment was used for cell operation to resolve the rate-determining step of discharge process. High stability and excellent high-rate performance can be achieved with sufficient oxygen provision. Lastly, designing criteria of suitable catalyst in oxygen-rich environment was explored. Catalyst with high oxygen affinity is preferred because the cell performance can be better enhanced under higher oxygen pressure.