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

Abstract 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.