In-depth insights into the impact of FEC on lithium metal electrodes by the utilization of an uncontaminated preformed SEI

The rising demand for high-performance energy storage solutions has led to a revival of the lithium metal battery (LMB), due to the beneficial synergistic properties of lithium metal with a high specific capacity (3860 mAh/g) and the lowest reduction potential (-3.04 V vs. standard hydrogen electrode (SHE)).&nbsp”;”The viability of lithium metal anodes is largely impacted by their surface properties during galvanostatic cycling, mainly the Li deposition morphology and the composition of the formed Solid Electrolyte Interphase (SEI). Thus, intensified research has been directed to tune and improve the interphasial properties, where the optimization of the electrolyte composition has been identified as one of the most impactful approaches. Beside the variation of the conducting salt and solvents/co-solvents, the incorporation of functional additives is regarded as an effective and cost favorable approach without deteriorating the bulk electrolyte properties.

The film-forming additive/co-solvent fluoroethylene carbonate (FEC) has shown to promote a homogeneous and dense lithium deposition morphology in LMBs.&nbsp”;”Within this work, a novel in-house designed lithium pretreatment method&nbsp”;”has been utilized to systematically evaluate the effect of FEC on the properties of the interphase and its influence on the cycling performance of the cell. The introduction of a FEC-induced preformed SEI in combination with FEC present during galvanostatic cycling drastically enhances the homogeneity of the lithium deposits and leads to faster ionic conductivity through the interphase, which eventually prolongs the cycle life of the corresponding NMC811||Li cell chemistry in a considerable fashion.