Nanorod-assembled Co3O4 hexapods with enhanced electrochemical performance for lithium-ion batteries

Highly symmetric Co3O4 hexapods assembled by numerous porous nanorods were successfully grown on copper foil through a facile hydrothermal method followed by thermal treatment. The as-prepared Co3O4 hexapods were characterized by X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy and transmission electron microscopy. Directly configured as binder-free anodes for lithium-ion batteries, the as-grown Co3O4 hexapods on copper foil exhibited a very high reversible capacity of 800 mA h g(-1) at 100 mA g(-1) and 440 mA h g(-1) at 500 mA g(-1) even after 40 cycles. The good electrochemical performance is attributed to the unique porous structure of the Co3O4 hexapods and the good contact with Cu foil. The performance could be further improved by carbon coating, exhibiting an enhanced reversible capacity of 1001 mA h g(-1) after even 40 cycles. The synthetic strategy holds the potential for large scale production of other transition metal oxides as high performance anodes for lithium-ion batteries.