Investigation Into the Properties of γ‐Valerolactone and γ‐Butyrolactone Imide‐Based Electrolytes for Lithium‐Ion Batteries

This study presents a detailed comparative study of lactone‐based electrolytes (γ‐valerolactone, GVL and γ‐butyrolactone, GBL) combined with lithium imide‐based salts, namely lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) and lithium bis(fluoromethanesulfonyl)imide (LiFSI). Propylene carbonate is employed as a reference electrolyte solvent. The physicochemical properties of these electrolyte systems are determined experimentally and further calculated using our developed computational model. Besides, in‐silico investigations are used to reveal valuable insights into the molecular interactions of the electrolyte components, such as self‐diffusion coefficients and radial distribution functions. Furthermore, the suitability of lactone‐based electrolytes for electrochemical applications is demonstrated by their promising rate capability and cycling stability over 200 cycles in graphite half‐cells, especially with 1 M LiTFSI and 2 wt% vinylene carbonate, together with their favorable performance on lithium iron phosphate. An excellent capacity retention achieved in a full‐cell configuration (> 80% after 200 cycles) further validates the potential of lactones as battery solvent alternatives, with GVL standing out due to its bio‐based origin.