Three-dimensional hierarchical Co3O4/CuO nanowire heterostructure arrays on nickel foam for high-performance lithium ion batteries

Novel three-dimensional (3D) hierarchical Co₃O₄/CuO nanowire (NW) arrays on nickel foam composed of CuO NW stems and Co₃O₄ nanosheet branches are synthesized by combining a facile, scalable, and cost-effective thermal oxidation method with a simple but powerful chemical bath deposition followed by a calcination process. These arrays are further investigated as binder- and conductive-agent-free anodes for lithium-ion batteries (LIBs). The smart hybridization of CuO NWs and Co₃O₄ nanosheets into hierarchical core/shell array configuration results in remarkably enhanced electrochemical performances with good cycle performance, high reversible capacity, and excellent rate capability compared with pure CuO NW and single net-like Co₃O₄ nanosheets. A high reversible capacity of 1191mAhg^-1 with 90.9% capacity retention after 200 cycles at a current density of 200mAg^-1, and reversible capacity up to 810mAhg^-1 even after 500 cycles at a current density as high as 1000mAg^-1 can be maintained. The superior electrochemical performances of electrodes composed of hierarchical Co₃O₄/CuO NW arrays connected directly on nickel foam make them potential anode materials for high-performance LIBs. © 2014 Elsevier Ltd.