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

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.