Copper oxide nanowire arrays synthesized by in-situ thermal oxidation as an anode material for lithium-ion batteries

• Dense CuO nanowire arrays are prepared by in-situ thermal oxidation.
• Cu2O layer is removed by ammonia to improve the lithium storage performance.
• The product exhibits high specific capacity and high-rate performance.
• The capacity does not fade but increases gradually after an initial drop.

Copper oxide nanowires with an average length of 7.4 μm are prepared by in-situ thermal oxidation at 500 °C for 6 h in air, and their lithium storage performances are promoted by a further ammonia treatment. The morphologies, structures and lithium storage properties of copper oxide nanowire arrays are investigated by X-ray diffraction, scanning electron microscopy, high-resolution transmission electron microscopy and a series of electrochemical measurements. The results show that after the reprocessing, the CuO nanowire arrays exhibit a higher reversible capacity of 645 mAhg−1 after 100 cycles at a current density of 50 mAg−1, excellent cyclability and high-rate capability. The good electrochemical performance and simple preparation process make it a promising anode material for lithium-ion batteries.