Tunable supercapacitor performance of potentiodynamically deposited urea-doped cobalt hydroxide

Abstract

Cobalt hydroxide with or without adding urea was potentiodynamically synthesized from a nitrate bath, and the resultant hydroxides were examined as electrode material for supercapacitor applications. The deposited hydroxides were characterized by X-ray diffraction, field-emission scanning electron microscopy and Fourier transformed infra-red spectroscopy. With urea in the nitrate bath, the specific capacitance of Co(OH)₂ could be tuned from 700 F g⁻¹ to 1200 F g⁻¹ at a current of 0.5 mA. It was shown that the addition of just 2 wt% urea in the nitrate bath had a strong influence on the supercapacitor performance, exhibiting the highest specific capacitance of 1200 F g⁻¹. The high-performance of the urea-doped Co(OH)₂ was attributed to the better access of electrolyte due to well-stabilized basal length.