Electrochemical supercapacitors of cobalt hydroxide nanoplates grown on conducting cadmium oxide base-electrodes

Abstract

Dopant-free and cost-effective sprayed cadmium oxide (CdO) conducting base-electrodes, obtained at different concentrations (0.5, 1 and 1.5 M), characterized for their structures, morphologies and conductivities by using X-ray diffraction, scanning electron microscopy and electrical conductivity measurements, respectively, are employed as base-electrodes for growing cobalt hydroxide (Co(OH)2) nanoplates using a simple electrodeposition method which further are envisaged for electrochemical supercapacitor application. Polycrystalline nature and mushroom-like plane-views are confirmed from the structure and morphology analyses. Both CdO and CdO–Co(OH)2 electrodes reveal specific capacitances as high as 312 F g−1 and 1119 F g−1, respectively, in 0.1 M KOH electrolyte at 10 mV s−1 sweep rate. Optimized Co(OH)2–CdO configuration electrode demonstrates energy density of 98.83 W h kg−1 and power density of 0.75 kW kg−1. In order to investigate the charge transfer kinematics electrochemical impedance measurements are carried out and explored.