Anodic stripping of zinc deposits for aqueous batteries: effects of anions, additives, current densities, and plating modes

Effects of anions of Zn salts and additives in the plating baths, current densities and modes of electroplating on the anodic stripping behavior of Zn deposits were investigated for the possible application to Zn-based batteries. The anodic stripping behavior was examined using linear sweep voltammetry (LSV) in a 0.5 M Na2SO4 solution containing 0.5 M ethylene-diamine-tetraacetic acid (EDTA). Effects of the above deposition variables on the discharge efficiency of Zn deposits were systematically compared on the basis of the chronopotentiometric (CP) curves measured galvanostatically at 1 C. Morphologies of all deposits were examined by scanning electron microscopy (SEM). Formation of Zn dendrites is depressed significantly by employing suitable additives (e.g., potassium sodium tartrate, tetrahydrate (PSTT)) as well as by using a cyclic voltammetric (CV) deposition. From the results of SEM and CP analyses, Zn deposit plated in CV mode shows the highest discharge efficiency, attributable to cubic grains with very clear boundaries, which is expected to easily strip under the anodic polarization.