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

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-O-2 battery. This composite structure exhibited enhanced performance with a specific capacity of 2453 mA h g(-1) at 0.1 mA cm(-1) 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.