Electrochemically deposited nanowhiskers of nickel oxide as a high-power pseudocapacitive electrode

High performance pseudocapacitive characteristics of potentiodynamically deposited NiO are reported here. Three-dimensional nanowhiskers of NiO were prepared by potentiodynamically depositing nickel hydroxide on stainless steel (SS) and heating the hydroxide in air at 300 degreesC for 3 h. The scan rate used for the deposition was 200 mV s(-1) and the electrolyte solution used was 100 mM NiCl2.6H(2)O at a pH 8.0. The NiO-covered SS electrodes were characterized by cyclic voltammetry (CV) in 1 M KOH electrolyte for the redox supercapacitor application. A maximum specific capacitance (SC) of 138 F g(-1) was obtained from the CV at a scan rate of 100 mV s(-1). A SC value of 82 F g(-1) was obtained even at the very high CV scan rate of 500 mV s(-1), demonstrating the high-power characteristics of NiO. Long cycle-life of the NiO nanowhiskers was also demonstrated. High specific capacitance, high power, high stability, and low cost of the electrode materials are favorable factors for commercial applications. (C) 2004 American Institute of Physics.