Synthesis of CoOx from ethaline on a stainless steel mesh for supercapacitor applications

Room Temperature Ionic liquids (RTIL) are molten salts that are liquid at around room temperature and consist of asymmetric anions and cations. Low volatility and wide electrochemical potential behaviour of RTIL make them preferable in reaction synthesis and electrochemical applications. In this study, cobalt was electrochemically deposited on an inexpensive stainless steel mesh substrate. The resultant modified electrode was studied for supercapacitor applications by measuring its capacitance performance. Choline chloride and ethylene glycol-based ionic liquid called Ethaline was used as the deposition electrolyte, and the ionic liquid was contained a cobalt salt (CoCl2) for cobalt growth. The deposition conditions of cobalt in Ethaline ionic liquid were found by cyclic voltammogram study. The cobalt in an ionic liquid was obtained by applying − 1.50 V potential on the stainless steel mesh by potentiostatic method. The uncoated and cobalt-coated steel mesh electrodes were then tested in KOH electrolyte to find appropriate potential window of the modified electrode. The cobalt-based material coated mesh electrode was scanned in 1 M KOH electrolyte between − 0.20 and 0.60 V and reported to have high electrochemical activity than uncoated mesh. The surface morphology of coated and uncoated mesh electrode was examined. Electrochemical characterizations of modified mesh electrodes were investigated using cyclic voltammetry. As a result, the obtained cobalt-coated mesh electrode had an areal capacitance of 650 mF cm−2 at scan rate of 5 mV s−1. The cobalt-coated steel mesh electrode may have potential application in OH−-based electrolyte for energy storage devices.