Exploring the mechanical properties of zinc metal across various length scales and strain rates for battery applications

Abstract

Zinc is a multivalent metal that holds significant promise as an anode material in rechargeable batteries owing to its high capacity. Likewise, zinc-based batteries’ compatibility with aqueous electrolytes enhances their safety by minimizing the risk of thermal runaway, a common concern in alkali-metal-based batteries. Bulk-scale mechanical properties of Zn have been well-studied. However, electrodeposits that form during electrochemical cycling often initiate at the nano-scale and grow to bulk-scales; as such, herein we investigated the mechanical properties of Zn metal across length-scales, from nano to bulk, utilizing various mechanical testing techniques. Our findings revealed that Zn exhibits a comparably moderate ‘size effect’ of hardness between the nano and bulk scales but that its mechanical properties are significantly sensitive to strain rate. We conclude by discussing the implications of these findings in the context of secondary battery applications.