Transesterification Induced Multifunctional Additives Enable High‐Performance Lithium Metal Batteries

The electrolyte chemistry is crucially important for promoting the practical application of lithium metal batteries (LMBs). Here, we demonstrate for the first time that 1,3‐dimethylimidazolium dimethyl phosphate (DIDP) and trimethylsilyl trifluoroacetate (TMSF) can undergo in situ transesterification in carbonate electrolyte to generate dimethyl trimethylsilyl phosphate (DTMSP) and 1,3‐dimethylimidazolium trifluoroacetate (DITFA) as multifunctional additives for LMBs. H2O and HF can be removed by the Si−O group in DTMSP to improve the moisture resistance of electrolyte and the stability of cathode. Furthermore, the dissolution of lithium nitrate (LiNO3) in carbonate electrolyte can be promoted by the trifluoroacetate anion (TFA−) in DITFA, thereby optimizing the solvation structure and transport kinetics of Li+. More importantly, both DTMSP and DITFA tend to preferential redox decomposition due to the low lowest unoccupied molecular orbital (LUMO) and high highest occupied molecular orbital (HOMO). Consequently, a thin and robust layer rich in P/N/Si on the cathode and an inorganic‐rich layer (e.g. Li3N/Li3P) on the anode can be constructed and superior electrochemical performances are achieved. This artificial transesterification strategy to introduce favorable additives paves an efficient and ingenious route to high‐performance electrolyte for LMBs. 1,3‐dimethylimidazole dimethylphosphate (DIDP) and trimethylsilyl trifluoroacetate (TMSF) can undergo in situ transesterification in carbonate electrolyte to generate dimethyltrimethylsilyl phosphate (DTMSP) and 1,3‐dimethylimidazole trifluoroacetate (DITFA) as multifunctional additives for LMBs. Among them, DTMSP removes H2O and HF, and DITFA promotes the dissolution of LiNO3 in carbonate electrolyte. Both DTMSP and DITFA have low lowest unoccupied molecular orbital (LUMO) and high highest occupied molecular orbital (HOMO), tending to preferentially redox decompose to produce a high‐quality electrode electrolyte interphase layer.