Hierarchical CoP@Ni(OH)2·0.75H2O core-shell nanosheet arrays on carbon cloth for high-performance supercapacitors

Abstract

The research on the structure tuning of CoP in supercapacitors has received extensive attention. However, low specific capacitance and energy density limit its further development. Here, we successfully synthesize the CoP@Ni(OH)₂·0.75H₂O core-shell nanosheets structure on carbon cloth. CoP nanowires, as the core, can provide efficient charge transportation path for electron transfer, while the thin Ni(OH)₂·0.75H₂O nanosheets shell can increase the specific surface area and curtail the transport distance. As a result, the as-prepared CoP@Ni(OH)₂·0.75H₂O nanosheet arrays electrode presents an outstanding specific capacity of 168.61 mAh g^-1 at 1 A g^-1. The assembled asymmetric supercapacitor (ASC) of CoP@Ni(OH)₂·0.75H₂O//activated carbon displays the highest energy density of 33.78 W h kg^-1 at 800 W kg^-1, as well as the remarkable cycling stability (capacitance retention of 98.5% after 10,000 cycles). Furthermore, ten parallel LEDs can be powered up by two ASCs connected in series. Thus, this article provides a new idea for the core-shell structure prepared by using CoP as the skeleton.