Electrochemical behavior of potentiodynamically deposited cobalt oxyhydroxide (CoOOH) thin films for supercapacitor application

In the present study, we report, for the first time, the synthesis of cobalt oxyhydroxide thin films on inexpensive stainless steel substrate using potentiodynamic electrodeposition method. These films were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM) techniques. The orthorhombic crystal structure was revealed by the X-ray diffraction study. The FT-IR spectrum confirmed the formation of cobalt oxyhydroxide. The SEM studies showed the nanoflakes-like morphology with an average thickness of 100 nm. The cyclic voltammetry study of the cobalt oxyhydroxide films in 1 M KOH showed maximum specific capacitance of 449 F g−1 at scan rate of 5 mV s−1.

Graphical abstractScanning electron micrograph (SEM) images of cobalt oxyhydroxide thin film at (a) 2000× and (b) 10,000× magnifications.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Simple method for the synthesis of CoOOH thin films. ► Supercapacitor with maximum specific capacitance of 449 F g−1. ► High charge/discharge efficiency.