Nonflammable Electrolytes With Weakly Lithiophilic Diluents for Stabilizing Silicon-Based Lithium-Ion Batteries

Stabilization of the silicon-based anode in lithium-ion batteries heavily depends on electrolyte engineering. However, despite the effectiveness of localized high-concentration electrolytes in enhancing battery life, most studies have focused on solvents and lithium salts, highlighting the urgent need for advanced diluents tailored to silicon-based anodes. Here, a nonflammable electrolyte with a weakly lithiophilic diluent is reported by introducing methyl perfluorobutyl ether into a mixture of lithium bis(fluorosulfonyl)imide and 1,2-dimethoxyethane, for the enhancement of silicon-based anode. The diluents, exhibiting weak solvation tendency, are capable of forming large cluster-like structures in the outermost layer of the solvation shell by interacting with the solvents and lithium salts. Therefore, the weakly lithiophilic diluent accelerates the transport of lithium-ions and increases the probability of lithium-ions coordinating with anions, leaving a robust inorganic-rich solid electrolyte interphase on the silicon-based anode. high areal capacity (4.2 mAh cm⁻²) cells are constructed with silicon-based anodes and nickel-rich cathodes employing this electrolyte, exhibiting impressive cycling stability with 82.1% capacity retention after 200 cycles.