Electrochemical synthesis of γ-CoOOH films from α-Co(OH)2 with a high electrochemical performance for energy storage device applications

Abstract

In this work, γ-CoOOH was successfully synthesized from α-Co(OH)2, as a precursor, by electrochemical oxidation, without the use of any additives or high temperatures. The films were morphologically and structurally characterized using X-Ray Diffraction and Scanning Electronic Microscopy techniques. Cyclic voltammetry, galvanostatic charge–discharge, and electrochemical impedance spectroscopy techniques were used for the electrochemical characterization. The XRD and Raman techniques allowed confirming the effective conversion of α-Co(OH)2 to γ-CoOOH. The γ-CoOOH films are composed of hexagonal platelets on a steel plate substrate. The deposited films exhibit excellent electrochemical performance at different current densities, and good cycling stability of 95.1% after 2000 cycles of charge/discharge. The maximum specific capacity of 89.3 mA h g−1 was achieved at a current density of 1 mA g−1. The results suggest a simple route to synthesize γ-CoOOH films, which are promising as an electrode material for application in energy storage devices.