Institute of Electrical Engineering, CAS: Progress Made in Low-Temperature Lithium-Ion Capacitor Electrolyte Research

Institute of Electrical Engineering, CAS: Progress Made in Low-Temperature Lithium-Ion Capacitor Electrolyte Research, with Energy Density Reaching 8.9 Times That of Conventional Electrolytes

According to the Institute of Electrical Engineering of the Chinese Academy of Sciences, researcher Ma Yanwei's team recently proposed a "solvation-deshielding electrolyte" design strategy. The team adopted gamma-valerolactone (GVL), which combines moderate polarity, a low melting point, and appropriate coordination ability, as the main solvent, used lithium difluoro(oxalato)borate (LiDFOB) as the functional lithium salt, and introduced weakly coordinating ethyl acetate (EA) as a solvation-regulating component to weaken the wrapping and shielding effect of the solvent on lithium ions, promote anion participation in constructing the local solvation structure, and form a weakly bound, anion-involved solvation-deshielding environment. This design effectively reduced the desolvation barrier and interfacial charge transfer resistance under low-temperature conditions and improved the stability of the electrode-electrolyte interface. The study showed that all-carbon lithium-ion capacitors prepared with this solvation-deshielding electrolyte still maintained excellent energy output performance at -40 degrees Celsius, achieving an energy density of 106.8 Wh/kg based on the mass of electrode materials, which is 8.9 times that of conventional carbonate-based electrolytes.