Comprehensive Analysis of Heat-Treated Lithium Metal: Surface Characteristics and Evolution of the Solid Electrolyte Interphase

Lithium metal batteries (LMBs) are promising candidates for next-generation energy storage devices because of their high energy density. However, the formation of dendritic lithium during charge-discharge cycles poses significant safety risks. This study investigates the effects of thermal treatment on the surface morphology and Solid Electrolyte Interphase (SEI) formation of lithium metal anodes using Atomic Force Microscopy (AFM). Lithium metal samples were heat-treated at 100°C for 24 hours and then immersed in an electrolyte solution for different durations. AFM analysis revealed that thermal treatment increases the size and uniformity of nucleation sites. This results in a thicker and more stable native oxide layer. This enhanced layer promotes a more uniform and densely packed SEI, which remains stable over long-term immersion. The findings highlight the potential of thermal treatment to improve the performance and safety of lithium metal anodes by stabilizing the SEI and preventing dendritic growth. This advancement could significantly enhance the practical application of LMBs.