Ionic liquids (ILs) are promising alternatives to conventional organic electrolytes for next-generation energy storage systems owing to their high thermal stability, negligible vapor pressure, and favorable ionic conductivity. In this study, classical molecular dynamics simulations based on the GAFF force field, combined with density functional theory (DFT) calculations, were employed to investigate IL-based electrolytes comprising imidazolium and pyrrolidinium cations paired with [TFSI]???? and [FSI]???? anions in the presence of lithium salt at mole fractions of X = 0.2–0.8. Theoretical results indicate that [FSI]???? -based electrolytes exhibit superior transport properties compared with [TFSI]???? -based systems. Specifically, [Emim][FSI] shows a self-diffusion coefficient of 1.62 × 10???? 11 m2 s???? 1 and an ionic conductivity of 0.60 S.m???? 1, whereas [Emim][TFSI] shows 4.75 × 10???? 12 m2.s???? 1 and 0.14 S.m???? 1. Among the lithium-containing systems, ILs with [Emim]+ and [C2mpyr]+ cations exhibited the highest conductivities and diffusivities. Structural analysis indicates that strong Li+–anion interactions promote aggregation and enhance Li+ transference numbers through a dominant hopping transport mechanism at high lithium concentrations (X = 0.8). These findings provide valuable insights into the rational design of IL-based electrolytes with improved conductivity and stability for advanced lithium battery applications.

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