Solid-Electrolyte Interphase of Molecular Crowding Electrolytes

摘要

Molecular crowding electrolytes extend the stability window of aqueousbatteries with water-miscible/soluble polymers at a low concentration of lithium salts 2m lithium bis(trifluoromethane sulfonyl)imide (LiTPSI). Water decompositionespecially hydrogen evolution reaction (HER) is effectively suppressed, enablingthe use of numerous negative electrodes which cannot work in traditional aqueouselectrolytes. However, the mechanism underlying the cathodic stability of molecularcrowding electrolytes is not yet fully understood. Here, we compare the HERsuppression effect in molecular crowding electrolytes with LiTFSI and lithiumperchlorate and correlate their distinct cathodic stability to the difference in the solid-electrolyte interphase (SEI). This workreveals the critical role of LiF in developing a stable SEI and suppressing the HER in molecular crowding electrolytes, providing adesign path for safe, low-cost, and high-voltage aqueous batteries.