Electrophoretic deposition of hierarchical Co₃O₄@graphene hybrid films as binder-free anodes for high-performance lithium-ion batteries

A facile approach is developed for large-scale fabrication of Co₃O₄@graphene hybrid films via one-step electrophoretic deposition and subsequent thermal annealing. The formation mechanism was discussed in detail. The as-prepared hybrid films exhibit unique hierarchical morphology, in which the Co₃O₄ nanoparticles with a size of 10-20 nm uniformly anchor on the surface and interlayer of graphene. When evaluated as binder-free anodes for lithium-ion batteries, the Co₃O₄@graphene hybrid films exhibit excellent lithium storage performance. Especially, the Co₃O₄@graphene hybrid films with 23.18 wt% graphene exhibited a high reversible capacity of 1059 mA h g^-1 at a high current density of 500 mA g^-1, a good capacity retention of 84.3% after 50 cycles, and excellent rate capability. It is worth mentioning that the content of graphene in the hybrid films plays a great role in its lithium storage performance due to its structural advantages and high conductivity.