CuO nanowire arrays synthesized at room temperature as a high-performance anode material for Li/Na-ion batteries

CuO nanowire arrays with thin nanowires and large interspaces grown on copper foil are prepared by a one-step room temperature solution approach without subsequent annealing. As the anodes for Li/Na-ion batteries, the large empty spaces between the nanowires enable Li/Na ions to diffuse into the electrode quickly. Due to the narrow diameter of the nanowire, the volume could expand in a timely manner, and the large interspace between the nanowires could accommodate the expansion effectively; thus, an undamaged framework is maintained. The one-dimensional nanowire and the tight contact between the nanowire and substrate favor electron delivery. A high discharge-charge capacity (i.e., at 100 mA g(-1) it was 760 mAh g(-1) for the Li-ion batteries and 351 mAh g(-1) for the Na-ion batteries), excellent rate performance and long cycling life are obtained. This onestep synthesis route at room temperature is straightforward and industrially scalable. These factors, combined with the excellent electrochemical performance, make CuO nanowire arrays a promising anode for Li/Na-ion batteries.