Solid-Electrolyte Interphase for Ultra-Stable Aqueous Dual-Ion Storage

摘要

The solid-electrolyte interphase (SEI) is the key component of the electrochemicalelectrode as a passivation layer, which enables a long calendar life for commercialapplications. However, owing to the poor understanding of aqueousSEI in conventional aqueous electrolytes, the adoption of aqueous Li-ion batteries(ALIBs) has been drastically limited. Herein, the construction of a robustaqueous SEI is successfully demonstrated by introducing a ladderized heterocyclicpolymer electrode into a water-in-salt electrolyte, leading to ultra-stabledual-ion storage with long-term calendar life. The sophisticated SEI composedof fluorinated/oxygenated species is revealed. Electrochemical and structuralanalysis confirm that such SEI formation is characterized by a proton cointercalation,which consumes the water in the Li~+’s solvation shell to triggerthe subsequent decomposition of organic anions. This new SEI formation pathis expected to broaden the horizons of aqueous SEI and open new avenues forthe design of versatile electrode materials for further advances in ALIBs.