biostudies-literatureSankaran AScience Foundation IrelandEuropean Union's Horizon 2020 Research and Innovation Programe22709https://www.ebi.ac.uk/biostudies/studies/S-EPMC12828446biostudies-literatureUnknown65(4)A sturdy solid electrolyte interphase (SEI) is imperative for extending the calendar-life of Si anodes in lithium-ion batteries (LIBs). However, carbonate electrolytes form unstable interphases, hindering their practical implementation. Alternatively, fluorinated sulfonylimide (FSI^-/TFSI^-) based ionic liquid (IL) electrolytes, coupled with Li-imide salts, enable anion-derived SEI formation, thereby enhancing capacity retention. However, the functional role of these anions in directing SEI formation and evolution within IL-based systems is poorly understood. Moreover, the mechanistic interplay between the decomposition pathways of symmetric and asymmetric anions in governing interfacial chemistry remains elusive. Herein, we investigate the chemistry and morphology of SAngewandte Chemie (International ed. in English)Symmetric Vs Asymmetric Imide Anion Decomposition Pathways And Their Influence On Solid Electrolyte Interphase Stability For Si Anodes.PMC1282844616/IA/4629IRCLA/2017/285SFI 16/M-ERA/341912/RC/2278_P216/RC/391818/SIRG/548412/RC/2302_P2814464Van der Velden MAppetecchi GBLaffir FAdegoke TEIsrael SSKapuria NMaresca GGeaney HRyan KMSankaran AfalseSymmetric Vs Asymmetric Imide Anion Decomposition Pathways And Their Influence On Solid Electrolyte Interphase Stability For Si Anodes.A sturdy solid electrolyte interphase (SEI) is imperative for extending the calendar-life of Si anodes in lithium-ion batteries (LIBs). However, carbonate electrolytes form unstable interphases, hindering their practical implementation. Alternatively, fluorinated sulfonylimide (FSI^-/TFSI^-) based ionic liquid (IL) electrolytes, coupled with Li-imide salts, enable anion-derived SEI formation, thereby enhancing capacity retention. However, the functional role of these anions in directing SEI formation and evolution within IL-based systems is poorly understood. Moreover, the mechanistic interplay between the decomposition pathways of symmetric and asymmetric anions in governing interfacial chemistry remains elusive. Herein, we investigate the chemistry and morphology of S2026-01-01T00:00:00Z2026 Jan2026-06-06T21:41:03.896Z2026-06-05T03:11:58.359ZS-EPMC128284464132790010.1002/anie.202522709