Enhancing supercapacitor performance through electrodeposition of cobalt hydroxide thin film: structural analysis, morphological characterization, and investigation of electrochemical properties

Dopant-free Co(OH) 2 was synthesized from a precursor of 0.1 M CoCl 2 on the single-sided conducting surface area of 1 cm 2 of stainless steel strip (SSS) substrate. It was developed by using a low-cost two-electrode technique at 0.5 V, 28 °C, 50 s reaction time, and in 50 ml double distilled water. Further, electrochemical properties are measured by a three-electrode technique. The charge/discharge characteristic testing of Co(OH) 2 at different current densities (1 A/g, 3 A/g, 5 A/g) were studied which results in shifting of peaks toward the positive direction. CV examination of Co(OH) 2 material as electrode was carried out at different scan rates (10 mV/s, 20 mV/s, 30 mV/s) in 0.1 M potassium hydroxide solution ranging − 0.2 to 0.5 V. A pair of redox peaks was noticeably observed in CV trace, demonstrating the typical capacitive behavior of Co(OH) 2 electrode. The specific capacitances (87.5 to 262.5 F/g), specific energy densities (28 to 84 Wh/kg), and specific power densities (0.08 to 0.24 W/kg) were measured from GCD. Additionally, morphological studies such as XRD, SEM, and EDS were investigated. The morphological results show Co(OH) 2 is having crystalline structure, average crystallite size of 37.88 nm, particle size of 180 nm, and elemental analysis confirms the presence of the elements. Further, it can be concluded that the Co(OH) 2 has good electrochemical performance which is suitable for supercapacitor electrode material. This cobalt hydroxide electrode is a favourable candidate for electrochemical energy-storage devices. Graphical abstract