Effects of Carboxymethyl Cellulose on the Electrochemical Characteristics and Dendrite Growth of Zinc in Alkaline Solution

Abstract

Carboxymethyl cellulose (CMC) is an important additive for zinc paste electrodes in alkaline zinc-based batteries. However, while its use is increasingly common in zinc paste electrodes, no research exists regarding the electrochemical effects of CMC on the zinc electrode surface. The present study investigates the influence of different contents of CMC in 6 M KOH on a pure zinc electrode with a flat surface. The corrosion potential, corrosion current density, and polarization resistance are assessed by Tafel extrapolation, which shows that CMC could reduce the corrosion current and lower the hydrogen evolution potential. Electrochemical impedance spectroscopy and potentiodynamic and galvanostatic anodic polarization confirm that CMC in the alkaline electrolyte could increase corrosion resistance but inhibit the discharge process of alkaline zinc-based batteries. Scanning electron microscopy indicates that 10 g L−1 or more CMC could suppress zinc electrodeposition kinetics and change the crystalline morphology. These results demonstrate that an appropriate amount of CMC in 6 M KOH can suppress the rates of corrosion and zinc dendrite growth.