Synthesis of Hierarchical Hausmannite Sulphur Reduced Graphene Oxide and Cobalt Nickel Layered Double Hydroxide Composite through Binary-Step Electrodeposition Approach for High-Yield Supercapacitor Applications

Wednesday, 12 October 2022: 14:40
Room 224 (The Hilton Atlanta)
G. Rutavi, D. J. Tarimo, V. M. Maphiri, and N. Manyala (University of Pretoria)
A composite electrode material comprising Hausmannite sulphur reduced graphene oxide (MO/RGO-S) and cobalt-nickel layered double hydroxide (CN) was integrated using a binary-step electrodeposition method. This procedure commenced with galvanostatic electrodeposition of MO/RGO-S on nickel foam (NF). This was followed by cyclic voltammetry (CV) electrodeposition of CN. The incorporation of RGO-S in the composite enhances the electrical conductivity of the active material (AM) and its wettability whereas MO increases the pseudocapacitive active sites which raises the specific capacity of CN. The electrochemical performance of the materials was evaluated in two- and three-electrode set-up using 2 M KOH electrolyte. A composite material (MO/RGO-S-50@CN) yielded a remarkable 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 produced specific energy of 56.0 Wh kg-1 corresponding to a specific power of 515.0 W kg-1 at a specific current of 0.5 A g-1. The device delivered a coulombic efficiency of 99.7 % and capacity retention of 85.1 % after 10 000 galvanostatic charge-discharges (GCD) cycles at 6 A g-1. Due to these phenomenal results, the assembled materials exhibited great capability for application in high-energy supercapacitors.