A facile synthetic strategy to three-dimensional porous ZnCo^sub 2^O^sub 4^ thin films on Ni foams for high-performance lithium-ion battery anodes

Three-dimensional (3D) porous ZnCo2O4 thin films on nickel foam substrates have been fabricated through a facile strategy of electrostatic spray deposition (ESD) followed by annealing in Ar atmosphere for lithium-ion battery anodes. The obtained ZnCo2O4 films on Ni foams show excellent cycling performance with a reversible capacity of over 1726 mAh g−1 after 100 cycles at 400 mA g−1. The ZnCo2O4 electrodes also present good rate capability with 811 mAh g−1 at 5 A g−1. The improved electrochemical performances should be ascribed to 3D porous ZnCo2O4 architecture directly grown on Ni foam current collector, due to the synergistic advantages of offering more reaction sites, effective void space to the volume variation during cycling, and improving of electron transport. It is proposed that this facile strategy of ESD technique can be extended to synthesize other 3D porous mixed transition-metal oxide materials.