Hierarchical core-shell-structured bimetallic nickel-cobalt phosphide nanoarrays coated with nickel sulfide for high-performance hybrid supercapacitors

High-performance supercapacitors have attracted considerable interests due to their high-power density, fast charge/discharge process and long cycle life. However, the wide application of supercapacitors is limited by their low energy density. Herein, the hierarchical core-shell structured NiCoP@NiS nanoarrays have been successfully synthesized by using the vertically grown nickel-cobalt bimetallic phosphide (NiCoP) nanowire as the core and the nickel sulfide (NiS) by electrodeposition as the shell. As the "super channel " for electron transfer, the NiCoP core is coupled with the NiS shell to promote rapid diffusion of electrons and improve cycle stability of the electrode. Consequently, the optimized NiCoP@NiS nanoar-rays display an extremely good specific capacitance (2128F g(-1 )at 1 A g(-1)) and a superior long cycle life (the capacitance retention of 90.36 % after 10,000 cycles). A hybrid supercapacitor (HSC) has been assembled using the NiCoP@NiS as the positive and the activated carbon (AC) as the negative, which displays a superior energy density of 30.47 Wh kg(-1 a)t a remarkable power energy of 800 W kg(-1). This study shows that the prepared hierarchical core-shell structured nanoarrays have great prospects as a novel electrode material in energy storage. (c) 2022 Elsevier Inc. All rights reserved.