In situ Growth of Cu₂O/CuO Nanosheets on Cu Coating Carbon Cloths as a Binder-Free Electrode for Asymmetric Supercapacitors

Cu₂O/CuO nanosheets in-situ grown on Cu-Carbon cloths (Cu-CCs), namely Cu₂O/CuO@Cu-CCs, are constructed by a simple strategy with electroless copper plating, chemical etching, and thermal dehydration. The as-prepared material is directly used as binder-free electrodes for supercapacitors (SCs). CCs coated with Cu, as the current collector, can effectively promote the charge collection and electron transfer, while the hierarchical Cu₂O/CuO nanosheets provide massive active sites for fast faradic reactions. The composite electrode exhibits high specific capacitance [1.71 F cm^-2, equivalent to 835.2 F g^-1, at the current density of 10 mA cm^-2 (3.57 A g^-1)]. The asymmetric supercapacitor device using Cu₂O/CuO@Cu-CCs as the positive electrode and activated carbon as the negative electrode, achieves a superior energy density up to 60.26 Wh kg^-1 at a power density of 299.73 W kg^-1 and an excellent long-term cycling stability (9.65% loss of its initial capacitance after 5,000 cycles). The excellent electrochemical performance is mainly ascribed to the unique hierarchical structure of Cu₂O/CuO@Cu-CCs, making it attractive as a potential electrode material for high performance SCs.