Physicochemical and electrocatalytic properties of Li-Co 3O 4 anodes prepared by chemical spray pyrolysis for application in alkaline water electrolysis

Abstract

An electrode kinetic study of oxygen evolution has been made on Li-Co 3O 4 thin films in KOH aqueous solutions with different concentrations. Oxide films with different amounts of Li were prepared on glass, by chemical spray pyrolysis at 300 °C, followed by a heat treatment at 400 °C in air. The Li doping increases the electrical conductivity of these materials. In what concerns the roughness factor, an increase is also observed up to 3% of Li. From steady-state current–potential measurements, Tafel slopes close to 2.3 RT/ F were obtained in the low current range, irrespective to electrolyte concentration and Li percentage, pointing to the same oxygen evolution mechanism onto all prepared oxides. The reaction order with respect to OH − was found to be approximately 1.7. The electrodes performance towards the oxygen evolution increases with the increase in Li content.