Abstract:

The self-corrosion rate, anodic dissolution rate, and passivating tendency of a zinc anode are important parameters that affect the performance of alkaline batteries. Effects of the addition of Carbopol resin to the electrolyte and the addition of passivation Bi passivation to the electrodes on the electrochemical behavior of Zn electrodes were investigated by linear polarization and chronopotentiometry. Surface morphologies of Zn electrodes and Zn-Bi alloy electrodes after etched and constant current dissolution were examined using a metallographic microscope and environmental scanning electron microscope (ESEM). Results showed that the addition of Carbopol resin significantly enhanced the polarization resistance, decreased the self-corrosion current, led to a positive shift in anodic dissolution potential, remarkably increased the anodic overpotential and promoted the passivation of alloy electrodes. The addition of Bi markedly improved the oxide film morphology and mass transfer between solid-liquid interfaces, decreased the self-corrosion rate of Zn electrodes and inhibited the self-corrosion process in Zn electrodes.

Key words: Passivation, Zinc-bismuth alloy electrode, Self-corrosion, Carbopol resin