Protecting Zn anodes by atomic layer deposition of ZrO2 to extend the lifetime of aqueous Zn-ion batteries

Abstract

Aqueous rechargeable Zn-ion batteries (ARZIBs) are a newly emerged class of electrochemical cells suited for large-scale stationary energy storage applications due to their unique advantages in safety, cost, and supply chain. To advance ARZIB technology toward commercialization, the corrosion problem of Zn anodes in aqueous electrolytes must be adequately addressed. Here we report our efforts to tackle this issue by using atomic layer deposition (ALD) to coat the Zn anode surface with a protective nanoscale ZrO₂ thin film, collectively denoted as ALD-ZrO₂@Zn in this study. We show the pertinent properties of ALD-ZrO₂@Zn in aqueous Zn-salt electrolyte solutions and electrochemical cells of three-electrode, symmetrical and full battery configurations. From these experiments, we have identified that 5–10 nm ALD-ZrO₂@Zn anodes exhibit the best performance with low corrosion rate and excellent cycle stability over a broad current density range. The post-experiment microstructural examinations reveal that the ALD-ZrO₂ coating effectively regulates the surface passive layer to grow into a thin, dense, and continuous form.