▎ 摘　　要

Li-CO2 batteries are attractive electrical energy storage devices; however, they still suffer from unsatisfactory electrochemical performance, and the kinetics of CO2 reduction and evolution reactions must be improved significantly. Herein, a composite of ruthenium-copper nanoparticles highly co-dispersed on graphene (Ru-Cu-G) as efficient air cathodes for Li-CO2 batteries is designed. The Li-CO2 batteries with Ru-Cu-G cathodes exhibit ultra-low overpotential and can be operated for 100 cycles with a fixed capacity of 1000 mAh g(-1) at 200 and 400 mA g(-1). The synergistic effect between Ru and Cu not only regulates the growth of discharge products, but also promotes CO2 reduction and evolution reactions by changing the electron cloud density of the surface between Ru and Cu. This work may provide new directions and strategies for developing highly efficient air cathodes for Li-CO2 batteries, or even practical Li-air batteries.