Purification and Characterization of Reclaimed Electrolytes from Spent Lithium-Ion Batteries

As an indispensable part of lithium-ion batteries (LIBs), closed-loop recycling, reusing the electrolyte from spent LIBs, has not yet been fulfilled experimentally. Herein, this paper presents a LIB electrolyte recycling approach which consists of supercritical CO₂ extraction, resin, and molecular sieve purification and components supplements. The resultant electrolyte exhibited a high ionic conductivity of 0.19 mS·cm^-1 at 20 °C, which was very close to a commercial electrolyte with the same composition. Moreover, the electrolyte was also electrochemically stable up to 5.4 V (vs Li/Li⁺) in the linear sweep voltammetry (LSV) measurement. The application potential of reclaimed electrolyte was demonstrated by Li/LiCoO₂ battery presenting the initial discharge capacity of 115 mAh·g^-1 with a capacity retention of 66% after 100 cycles at 0.2 C. This investigation is a crucial break for electrolyte recycling and opens a bright route toward realizing closed-loop LIB recycling.