A microscopic view of diffusion and failure mechanisms of lithium anodes in solid-state batteries

Although all-solid-state lithium metal batteries (SSLBs) have long been regarded as successors of the commercially available lithium-ion batteries (LIBs), SSLBs do not yet deliver sufficient and competitive performance. The use of a solid electrolyte in combination with lithium metal as the anode increases the theoretical energy density and improves safety. However, these advantages are overshadowed by various degradation mechanisms—especially dendrite formation. Hence, comprehending the phenomenon of dendrite nucleation and growth will be a decisive step toward the commercialization of SSLBs. This review summarizes the current understanding of dendrite formation at the solid electrolyte/lithium metal anode interface. Focusing on the microscopic level, it aims to compare and categorize different findings related to dendrite formation in inorganic, polymer (including dynamic and dynamic-crosslinked polymer), and hybrid solid electrolyte batteries. Different critical mechanisms are highlighted, such as inhomogeneous plating or stripping, as well as the interconnections between those failure mechanisms. Processes that result in dendrite formation or are a consequence of dendrite formation are included, and key mechanisms such as ionic transport, homogeneous plating and stripping, as well as interphase evolution and its connection to failure mechanisms are reviewed. • This review establishes key correlations between critical parameters and the processes that govern dendrite growth across various solid electrolytes. • It also examines the underlying physicochemical interplay of degradation mechanisms and their evolution during cycling, as well as their impact on battery performance. • Low lithium self-diffusion coupled with interfacial defects is identified as a key driver of dendrite formation.