Facile fabrication of CuO nanosheets on Cu substrate as anode materials for electrochemical energy storage

CuO nanosheets are synthesized on Cu substrate via a one-step corrosion process, which can be formed at room temperature. The reaction time and solution concentration show great effects on the microstructure of products. The obtained CuO nanosheets are systematically evaluated as anode materials for both lithium-ion battery (LIB) and sodium-ion battery (NIB). The CuO electrode undergoes multi-step conversion processes in both LIB and NIB, but their charge/discharge plateaus are quite different. In LIB, the CuO electrode exhibits a remarkable electrochemical performance. However, the CuO anode in NIB shows poor cyclability and rate capability, which is mainly due to the high interface impedance, large volume expansion and slow ion diffusion caused by the larger size of Na⁺ ion.