Two‐step electrodeposition of Hausmannite sulphur reduced graphene oxide and cobalt‐nickel layered double hydroxide heterostructure for high‐performance supercapacitor

Abstract

Hausmannite/sulphur reduced graphene oxide (MO/RGO-S) and cobalt-nickel layered double hydroxide (CN) composite was synthesized through a two-step electrodeposition approach. This process began with galvanostatic electrodeposition of MO/RGO-Son a nickel foam, followed by cyclic voltammetry electrodeposition of CN. The inclusion of RGO-S increases the electrical conductivity of the active material (AM) and its wettability while Mn3O4 (MO) enhances the pseudocapacitive active sites which help to increase the specific capacity of CN. The materials' electrochemical evaluations were carried out via three- and two-electrode configurations using 2 M KOH electrolyte. An enhanced composite material (MO/RGO-S-50@CN) produced a phenomenal specific capacity of 582.1 mA h g−1 in a three-electrode configuration at 0.5 A g−1. The device (MO/RGO-S-50@CN//CCBW) consisting of MO/RGO-S-50@CN and activated carbon from cooked chicken bone waste (CCBW) as positive and negative electrodes, respectively delivered specific energy of 56.0 Wh kg−1 with a specific power of 515.0 W kg−1 at a specific current of 0.5 A g−1. The device produced capacity retention of 85.1% and coulombic efficiency of 99.7% at 10 000 galvanostatic charge-discharges cycles at 6 A g−1. Because of these excellent results, the fabricated materials demonstrated great potential for application as a high specific energy supercapacitor.