Electrodeposition of ultrathin nickel–cobalt double hydroxide nanosheets on nickel foam as high-performance supercapacitor electrodes

Abstract

The present work demonstrates a facile, one-step electrodeposition approach for the preparation of ultrathin Ni–Co double hydroxide (DH) nanosheets on Ni foam as supercapacitor electrodes. The as-prepared Ni–Co DH electrodes in the electrolyte with Ni/Co ratio of 4/1 deliver an ultrahigh specific capacitance of 3028 F g⁻¹ at 2 A g⁻¹ as well as very good cyclic stability probably due to their robust and well-defined nanoporous structure and amorphous nature. The Ni–Co DH nanosheets also present an impressive energy density of 127.22 W h kg⁻¹ at 0.605 kW kg⁻¹, and the value still remains at 93.48 W h kg⁻¹ at a high power density of 15.125 kW kg⁻¹, indicating the excellent rate capability of these materials. In addition, the simple electrodeposition method involved in this study can potentially be scaled up for economic production of high performance supercapacitors.