To Be or Not to Be: Dendrite Growth Mechanism Adjacent to Pits for High Stability of Lithium Metal Anode

The challenge of dendrite growth is a formidable obstacle that leads to short circuits when charging lithium (Li)-metal batteries. Implementing patterns with various pit structures on Li metal proves to be an effective strategy to alleviate dendrite growth. Nonetheless, the growth mechanism of Li dendrites near pits is still under debate, making it difficult to accurately propose patterns to enhance the stability of the Li metal. In this study, the growth mechanism of dendrites near the pits is successfully clarified for the first time using the in situ optical microscopy method and electrochemical modeling. A direct correlation is established between the formation of Li dendrites and factors. Areas with heightened electric field strength and localized current density are more susceptible to dendrite formation. Increased local surface roughness promotes dendrite nucleation and growth. Dendrite growth at the edge of pits leads to an insufficient supply of Li ions in the pit, thereby inhibiting dendrite formation inside the pit. By optimization of the pattern structure, the density of Li deposition can be significantly improved. The results provide a promising and practical approach to ensure safety and extend the lifetime of Li metal batteries.