Effect of depth of discharge (DOD) on cycling in situ formed Li anodes

Abstract

Lithium-metal solid-state batteries (LMSSBs) have garnered immense interest due to their potential to enhance safety and energy density compared to traditional Li-ion batteries. The anode-free approach to manufacturing Li-metal anodes could provide the additional benefit of reducing cost. However, a lack of understanding of the mechano-electrochemical behavior related to the cycling of in situ formed Li anodes remains a significant challenge. To bridge this knowledge gap, this work aims to understand the cycling behavior of in situ formed Li anodes on garnet Li₇La₃Zr₂O₁₂ (LLZO) solid-electrolyte as a function of the depth of discharge (DOD). The results of this study show that cycling in situ formed Li of 3 mA h cm⁻² with a DOD of 66% leads to unstable cycling, while cycling with a DOD of 33% exhibits stable cycling. Furthermore, we observed interfacial deterioration and inhomogeneity of in situ formed Li anodes during cycling with a DOD of 66%. This study provides mechanistic insight into the factors that affect stable cycling that can help guide approaches to improve the cycling behavior of in situ formed Li anodes.