Quantitatively detecting and characterizing metallic lithium in lithium-based batteries

Abstract

Rechargeable lithium (Li)-based batteries, including Li-ion batteries (LIBs) and Li-metal batteries (LMBs), are essential energy storage devices. However, their electrochemical performance in practical applications is affected by the Li electroplating process and accompanying inevitable dendrite growth, which undermines their safety and longevity. Effective monitoring of electroplated Li formation, dendrite growth dynamics, and the evolution of inactive/active Li components is essential for understanding the degradation pathways of Li-based batteries and realizing their highly reversible prolonged lifespan. Recently, significant research progress has been achieved in the quantitative detection and characterization of dendrite Li growth and evolution, including the development of chemical quantification, electrochemical analysis, and characterization technique-based quantification methodologies. They provide new insights into how metallic Li formation affects the performance of Li-based batteries. This review article comprehensively summarizes the latest research advancements in quantitatively detecting and characterizing metallic Li formation and its effects on the performance of Li-based batteries. It provides an improved understanding of the failure mechanism induced by metallic Li formation. This review also discusses the positive effects of techniques on understanding failure mechanisms, critical unknown aspects, challenges, and potential future research directions necessary to overcome the limitations originating from metallic Li electroplating. We propose that future research should focus on refining quantitative detection techniques, controlling metallic Li formation, and enhancing the long-term stability of Li-based batteries.