Preparation of WO3 Films on Titanium and Graphite Foil for Fuel Cell and Supercapacitor Applications by Electrochemical (Cathodic) Deposition Method.

Numerous electrochemical and chemical methods are suitable for preparation of tungsten trioxide (WO3) films. Many of these methods, however, have not been carefully studied, so information on the specific features of the WO3 film deposition technology is lacking. This paper describes the preparation of WO3 films by cathodic electrodeposition from the synthesized solution of peroxotungstic acid (PTA) on the surface of thermally expanded graphite (TEG) and titanium electrodes designed as foils. A stepwise pattern of reduction of tungsten oxides from PTA was revealed. The suitability of the WO3 film electrode as a material for electrochemical power industry was experimentally demonstrated. Specifically, WO3/Ti was found to be applicable as a protective coating for hydrogen fuel cells, and WO3/TEG, as a cathode material for asymmetric supercapacitors. Based on the charge-discharge curves for the WO3/TEG electrode used as a cathode in the free volume of th KOH electrolyte, the specific capacitance of the supercapacitor was estimated at 630 F/g. Electrochemical analysis showed that that WO3 films deposited on the titanium surface afford enhancement of the hydrogen overpotential and protection against pitting corrosion during potentiostatic polarization tests at the cathode potential of a fuel cell. [ABSTRACT FROM AUTHOR]