Formulation and Recycling of a Novel Electrolyte Based on Bio‐Derived γ‐Valerolactone and Lithium Bis(trifluoromethanesulfonyl)imide for Lithium‐Ion Batteries

Abstract This work introduces a novel electrolyte comprising lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) salt dissolved in bio‐based γ‐valerolactone (GVL) for lithium‐ion batteries (LIBs). Moreover, a simple and sustainable aqueous‐based recycling approach for recovering the imide‐based lithium salt is proposed. Beyond the sustainable origin of the GVL solvent, this electrolyte exhibits reduced flammability risk, characterized by a flash point of 136 °C, along with favorable transport properties (conductivity of 6.2 mS cm ⁻¹ at 20 °C) and good electrochemical stability (5.0 V vs Li ⁺ /Li). Its good compatibility with graphite and lithium iron phosphate electrodes ensures remarkable cycling stability in LIB full‐cells after 200 galvanostatic cycles at 1 C. Furthermore, the proposed liquid–liquid phase electrolyte recycling method allows for a nearly complete recovery of the LiTFSI salt (97–99%) and the GVL solvent (78%). The feasibility of the recycling process is validated by the reutilization of the recovered LiTFSI salt in electric double‐layer capacitors, achieving performances similar to that of the pristine salt with exceptional long‐term stability.