Abstract
A major challenge in deploying aqueous Zn-ion batteries is the self corrosion of the Zn anode, largely influenced by the hydrogen evolution reaction (HER) mechanism. It is possible during battery cycling that the initial anodic dissolution will increase the subsequent cathodic reaction rates; this process is known as anodically-induced cathodic activation. While well-studied in other metals like Mg, this effect is relatively unexplored in Zn. This work examines the cathodic activation of Zn in 0.1 M NaCl (aq) and 1 M Na2SO4 (aq) across a pH range of 3 to 11. Our electrochemical testing demonstrates that sulfate environments trigger this activation universally across all tested pH levels. In contrast, chloride solutions only promote activation under neutral and alkaline conditions. Compositional and microstructural analyses indicate that this catalytic enhancement coincides from the precipitation of specific byproducts, namely Zn hydroxides.