Current density alters the mechanical stresses during electrodeposition of lithium metal anodes

Abstract

“Lithium metal” batteries operate via electroplating/stripping of Li metal and promise vast theoretical capacities. However, significant technical barriers must be addressed prior to commercialization. The primary challenges include the generation of mechanical stresses and strains due to "infinite volume expansion,” as well as non-uniform deposition of lithium metal, which often leads to dendrite formation and growth. Lithium dendrite formation is particularly critical, as dendrites can penetrate solid-state electrolytes, eventually shorting to the cathode, thereby diminishing the capacity of the battery and inducing severe safety hazards. These primary issues are intrinsically linked to the mechanical behavior of lithium; as such, this study focuses on the mechanical response of lithium electrodeposition under various electrochemical conditions. Experimental tests herein reveal that larger applied current densities induce significantly larger mechanical stresses during electroplating of Li metal. This manuscript concludes by detailing practical implications of these experimental observations, particularly regarding dendrite growth through solid-state electrolytes of solid-state batteries.