One-step electrodeposition strategy for growing nickel cobalt hydroxysulfide nanosheets for supercapacitor application

To meet the requirement of modern society, supercapacitors with long cycle life and excellent energy density are urgently required. Herein, a facile electrodeposition method was used to fabricate a suite of coral-like nickel cobalt hydroxysulfide nanosheet arrays (NiCo-SOH) on nickel foam (NF), which was expected to be a binder-free positive electrode for supercapacitors. NiCo-SOH (Ni:Co=1:1) nanosheets with layered double hydroxides structure display an excellent specific capacitance and superior rate capability (2092.7 F·g−1 at 1 A·g−1; 1696 F·g−1 at 10 A·g−1). Moreover, a NiCo-SOH (Ni:Co=1:1) electrode and active carbon (AC) was utilized to fabricate an asymmetric supercapacitor, which exhibits remarkable cyclic stability (98% capacitance retention after 9000 cycles) and excellent energy density of 34.3 W·h·kg−1. The considerable electrochemical performances and the ease of large-scale production make electrodeposited nickel cobalt hydroxysulfide hold great potential for commercialized supercapacitor applications.