Three-Dimensional Bi-Continuous Nanoporous Gold/Nickel Foam Supported MnO₂ for High Performance Supercapacitors

A three-dimensional bi-continuous nanoporous gold (NPG)/nickel foam is developed though the electrodeposition of a gold-tin alloy on Ni foam and subsequent chemical dealloying of tin. The newly-designed 3D metal structure is used to anchor MnO₂ nanosheets for high-performance supercapacitors. The formed ternary composite electrodes exhibit significantly-enhanced capacitance performance, rate capability, and excellent cycling stability. A specific capacitance of 442 Fg^-1 is achieved at a scan rate of 5 mV s^-1 and a relatively high mass loading of 865 μg cm^-2. After 2500 cycles, only a 1% decay is found at a scan rate of 50 mV s^-1. A high power density of 3513 W kg^-1 and an energy density of 25.73 Wh kg^-1 are realized for potential energy storage devices. The results demonstrate that the NPG/nickel foam hybrid structure significantly improves the dispersibility of MnO₂ and makes it promising for practical energy storage applications.