4.5‐V‐Class Safe Lithium‐Ion Batteries with Silicon‐Majority‐Graphite Anodes Enabled by Self‐Limiting Interphase
Lei Xu, Xue Han, Jaekyung Sung, Yong‐Sheng Hu, Jianqiang Wang, Qiao Han, Rui Gao, Yao Li, Weijiang Xue
Abstract
Abstract 4.5 V‐class lithium‐ion batteries (LIBs) pairing LiNi 0.8 Mn 0.1 Co 0.1 O 2 (NMC811) cathodes with silicon‐majority graphite (SmG, >1500 mAh g −1 ) anodes can surpass 400 Wh kg −1 , but their cycling stability, safety, and low‐temperature operation are constrained by the difficulty in constructing stable interphase. This study reports a hybrid‐sulfonamide electrolyte (HSE) that can survive the aggressive chemistry of high‐voltage NMC811 and programs a self‐limiting inorganic interphase on Si by leveraging the electron‐limited onset at the Si||electrolyte junction. At first lithiation, the semiconductor characteristic and native SiO x create a space‐charge (depletion) region, so the anionic‐structure‐like sulfonamides bias first‐electron reduction, seeding lithium halide/chalcogenide inorganics that are electronically insulating yet Li + ‐permeable. The resulting thin, dense layer suppresses electron tunneling, dissolution, and resists crack‐induced stress concentration during Si expansion—thereby self‐limiting further growth. Consequently, NMC811||SmG coin cells with the HSE retain 80% capacity after 500 cycles at 4.5 V and ≈5 mAh cm −2 and operate over a wide range of temperature from −40 to 60 °C, markedly outperforming the carbonate electrolyte. 1.4 Ah pouch cells maintain 80.0% of initial capacity after 1150 cycles and exhibit thermal stability up to 300 °C. This work establishes self‐limiting interphase formation on Si as a practical electrolyte design target for high‐energy LIBs.