ZnWO4-CNT as a superior electrode material for ultra-high capacitance supercapacitor

Abstract

In this study, we have synthesized zinc tungstate (ZnWO4) and zinc tungstate-carbon nanotube (ZnWO4-CNT) on the porous nickel foam (NF) to use as supercapacitor electrodes. The structural properties and morphology of samples were determined by Raman, XRD, SEM, EDX, and BET. The energy storage capability of ZnWO4/NF and ZnWO4-CNT/NF was investigated by electrochemical analyzes such as cyclic voltammetry (CV), galvanostatic charge-discharge analysis (GCD), and electrochemical impedance spectroscopy (EIS). Based on GCD analysis, ZnWO4-CNT/NF presented an excellent capacitance of 4552 F.g−1 at 1 A.g−1 in a 3 M potassium hydroxide (KOH) electrolyte and excellent stability of 92% after 3000 CV cycles at 100 mV.s−1. Furthermore, the supercapacitor application of ZnWO4-CNT/NF in an asymmetric supercapacitor (ASC) was investigated as the positive electrode and RGO/NF as the negative electrode, and the ASC presented a high capacitance of 320 F.g−1 at 1 A.g−1 in the potential window of 0_1.3 V with appropriate cycling stability of 78% after 3000 consecutive cycles. This study presented the great supercapacitive potential of ZnWO4-CNT/NF, which can be a promising electrode in supercapacitors.