Porous CuO/Cu2O heterostructured arrays as anode for high-performance sodium-ion batteries

Abstract

Herein, CuO/Cu2O heterostructured arrays were successfully realized by in situ sculpturing Cu foam based on the hydrothermal protocol. Owing to the state-of-the-art design, CuO/Cu2O nanosheet arrays are tightly and intimately grown on Cu substrate. The abundant holes formed by the unique three-dimensional construction of Cu foam and the porous CuO/Cu2O nanosheets are significantly beneficial to the infiltration of electrolyte and enhancement of the Na+ diffusion efficiency. It is noted that CuO/Cu2O electrode shows superior areal capacity than that of the individual CuO and Cu2O electrodes. At the current density of 0.6 mA cm−2, there is a reversible capacity of 1.0 mAh cm−2 (322.6 mAh g−1) for the CuO/Cu2O anode. Even at 2.0 mA cm−2, a reversible capacity of 0.56 mAh cm−2 (180.6 mAh g−1) can be still obtained. The full sodium-ion battery demonstrates a high reversible capacity of 0.53 mAh cm−2 (170.9 mAh g−1) in the initial cycle at 0.5 mA cm−2.