Effect of scan rate on the morphology of potentiodynamically deposited β-Co(OH)2 and corresponding supercapacitive performance

Nanoflakes (average thickness 100 nm) of cobalt hydroxide (β-Co(OH)2) were potentiodynamically deposited on stainless steel (SS) substrate. 0.1 M Co(NO3)2 was used as starting material and the scan rate of the deposition was varied between 20 and 200 mV s−1. These films were characterized for their structural and morphological study using X-ray diffraction and scanning electron microscope (SEM). The X-ray diffraction study revealed the formation of β-Co(OH)2 material with hexagonal crystal structure. Electrochemical properties of β-Co(OH)2 thin film electrode were studied using cyclic voltammetry and charge–discharge techniques. In present work, we studied effect of deposition scan rate on the morphology of the β-Co(OH)2. As the scan rate of the deposition increased, size of the nanoflakes became smaller and porous deposit was formed on the SS surface. Film deposited at high scan rate (200 mV s−1) showed maximum specific capacitance of 890 Fg−1 in 1 M KOH electrolyte at the scan rate of 5 mV s−1.