Effect of surface area on electrical properties of NiCo2O4-reduced graphene oxide nanocomposites for supercapacitor electrodes applications

Abstract

Based on the method of electrical charge storage, supercapacitors are divided into two categories, double-layer electrical capacitor (EDLC) and pseudocapacitors. Utilizing three processes—reversible adsorption, redox reactions on metal oxides, and reversible electrochemical—pseudocapacitors are utilized for high power applications involving metal oxide electrodes and the transfer of electric charge based on a reversible faradaic. In the fabrication of supercapacitors, a high specific surface area with a relatively narrow pore size distribution is essential. Therefore, it is required to increase the capacitance of the material. In this work, nickel cobaltite (NiCo2O4) synthesized from nanocomposite NiS·5H2O and Co2SO4·7H2O precursors were mixed with reduced graphene oxide (rGO). Coprecipitation and calcination were used to create the nanocomposites. The produced NiCo2O4/rGO nanocomposite was used as a pseudocapacitive supercapacitor electrode. The results showed that sample code S2 with mass variations of NiO, Co3O4, and rGO at a ratio of 2:3:2 had the best performance. The sample had a hexahedron-shaped surface morphology, an average particle size of about 0.005 m2, a specific surface area of 12.75 m2/g, an average pore radius of 9.534 nΩ.m, and a pore volume of 0.06404 cm3/g. It also performed exceptionally well in terms of electrical conductivity of 6.078 S/m, electrical resistivity of 0.16 nΩ.m, and capacitance of 289.93 F/g.

Keywords

• NiCo2O4/rGO nanocomposite
• Electric charge storage
• Pseudocapacitor electrode
• Specific capacitance
• Specific surface area