On Repeatability of Electrochemical Zinc Nucleation and Growth from Aqueous Zinc Sulfate Electrolytes

Electrodeposition of zinc is critical to enabling rechargeable zinc batteries. Historically, zinc batteries have employed zinc foil or powder zinc anodes, and the anode research has focused on improving the reversibility of zinc electrodeposition through a combination of material modifications and electrical controls. With the breakthroughs in anode-free lithium batteries, there is growing interest in leveraging the anode-free zinc batteries. The very first step in such an operation is nucleation and growth of zinc on a substrate, and it is essential to obtain repeatable electrochemical signatures to be able to conclusively study how this early stage electrodeposition is influenced by factors such as the electrolyte composition, substrate choice, and operating conditions. Surprisingly, our experiments electrodepositing zinc on stainless steel find appreciable cell-to-cell variability across identical testing conditions. The present study examines the role of surface cleaning, formation step, and zinc counter electrode to causing such variability in electrochemical signatures of zinc nucleation and growth.