The Electrode Reactions of Deposition and Dissolution of Zinc

Abstract

The electrode reactions of deposition and dissolution of zinc were studied by the faradaic impedance method. The electrode reaction in aqueous zinc sulfate solution was controlled by the charge-transfer reaction (Zn²⁺ + 2e^- ⇔ Zn) accompanied by an adsorption process. In the solution of alkaline zincate, the diffusion of Zn(OH)₄^2- toward the interface from the ulk and dissolution of the zinc hydroxide film on the zinc electrode were the rate-determining step in the processes of cathodic deposition and anodic dissolution, respectively. The charge transfer resistance and the diffusion resistance of zincate ion were remarkably decreased. when the solution temperature reached to 50°C, but the rate-determining step was almost independent of the temperature. The charge-transfer step was determined when the overpotential was larger up to about 5-10 mV.