Three-dimensional graphene–Co3O4 cathodes for rechargeable Li–O2 batteries

Abstract

A three-dimensional (3D) graphene–Co₃O₄ electrode was prepared by a two-step method in which graphene was initially deposited on a Ni foam with Co₃O₄ then grown on the resulting graphene structure. Cross-linked Co₃O₄ nanosheets with an open pore structure were fully and vertically distributed throughout the graphene skeleton. The free-standing and binder-free monolithic electrode was used directly as a cathode in a Li–O₂ battery. This composite structure exhibited enhanced performance with a specific capacity of 2453 mA h g⁻¹ at 0.1 mA cm⁻² and 62 stable cycles with 583 mA h g⁻¹ (1000 mA h g_carbon⁻¹). The excellent electrochemical performance is associated with the unique architecture and superior catalytic activity of the 3D electrode.