Zinc Oxidation in Limited Volume of Alkaline Electrolyte

Abstract

Studies of zinc electrode oxidation under the conditions of limited volume of alkaline electrolyte are carried out. It is shown, that at anodic polarization below 7–8 mV the zinc surface is covered by phase layer of zinc oxides and hydroxides. The last ones hinder diffusion of ions participating in electrochemical reactions. Then, formation of zincate complex [\(\rm{Zn}(OH)\begin{array}{c}2-\\ 4\end{array}\)] starts, with the slow diffusion stage of hydroxide ions to the anode surface. At polarization from 0.08 to 0.12 V formation of supersaturated zincate electrolyte occurs, and its decomposition with formation of the loose zinc oxide layer. At polarization above 0.12 V, nonporous oxide film is formed on zinc surface; zinc oxidation process proceeds by solid-phase mechanism.