Three-dimensional Ni(OH)2/Cu2O/CuO porous cluster grown on nickel foam for high performance supercapacitor

•A three-dimensional Ni(OH)2/Cu2O/CuO porous cluster was designed.•It was grown on nickel foam through a hydrothermal assistant redox reaction.•A high reversible redox couple CuO/Cu2O was introduced by nickel foam.•1474 Fg−1 at 15 mA cm−2 and 54% capacity remaining at 100 mA cm−2 are achieved.

A three-dimensional Ni(OH)2/Cu2O/CuO porous cluster was designed and directly grown on nickel foam (NF) through a facile, eco-friendly, one-step hydrothermal assistant redox reaction of NF with Cu(NO3)2 in the KOH solution, in which NF acted as both a reductant and Ni source. It exhibited improved rate capability and excellent specific capacitance, i.e. high capability (1474 Fg−1 at 15 mA cm−2), high cycling stability (82% retention after 1,500 cycles), and good rate capacitance (54% capacity remaining at 100 mA cm−2). The good electrochemical performance was due to the unique structure and components of it. The NF not only acted as a substrate for Ni(OH)2/CuO to germinate on and improved its electrical conductivity, but also introduced a new Cu2O phase to the composite. The inserted high reversible redox couple CuO/Cu2O enhanced the cycle performance of composite. The simple accessibility and ingenious design of this three-dimensional Ni(OH)2/Cu2O/CuO porous cluster proved that this was a promising method to obtain super supercapacitor electrode materials.

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