In situ fabrication of Ni(OH)2/Cu2O nanosheets on nanoporous NiCu alloy for high performance supercapacitor

The rapid depletion of fossil fuels along with critical environmental pollution has put forward urgent demands for advanced energy storage devices such as high-performance supercapacitors (SCs). Nickel hydroxides (Ni(OH)2) have been proved to be a high capacity electrode material for SCs, however, the preparation method and stability of Ni(OH)2 structures are unsatisfactory. In this work, via a low cost and one-step hydrothermal method in H2O2 aqueous solution without other reagents, vertically arranged Ni(OH)2/Cu2O nanosheets can be facilely fabricated on three-dimensional nanoporous NiCu alloy (NPNC), which exhibits large surface area and high electrical conductivity. Being the source of Ni and Cu, NPNC acts as the matrix of active materials as well. Thus, the strong combination and electron transportation between the active materials and NPNC can be achieved. Furthermore, the uniform distribution of Cu2O in the hybrids enhances the electrochemical stability of electrode. As a result, the binder-free Ni(OH)2/Cu2O/NPNC electrode materials exhibit a high capacity (8234 mC cm−2 or 823.4 C cm−3 at 20 mA cm−2) with excellent cycling stability (112.8% capacity retention after 10,000 cycles at 200 mA cm−2) and rate capability. Such desirable properties signify that the Ni(OH)2/Cu2O/NPNC composites hold great promise for the high-performance supercapacitors.