In‐Operando FTIR Study to Investigate the Effect of Varying Lithium Salts on Solid Electrolyte Interface (SEI) Evolution in Lithium Metal Batteries

shows a delayed interaction, with SEI formation commencing minutes into plating and featuring decomposition products such as LiCl. The LiDFOB electrolyte proves to be the least effective, yielding an unstable, organic-rich SEI that results in high overpotential and poor performance. This study establishes a clear correlation between SEI composition and electrochemical performance, offering a molecular-level understanding to inform rational electrolyte design and salt selection strategies for stable lithium metal batteries.