Highly Electronegative Anions Doping Effects in Sulfide‐Based Electrolytes: Toward High‐Voltage All‐Solid‐State Batteries

ABSTRACT The decomposition of sulfide‐based electrolytes (SEs), notably Li ₃ PS ₄ (LPS), at the electrode interface during battery cycling significantly hinders their practical application in all‐solid‐state batteries (ASSBs). However, the underlying mechanism through which chemical bonding modification enhances the electrochemical stability of SEs without compromising other properties remains unclear. Herein, we investigate the effect of introducing highly electronegative elements Q (Q ═ N, O, F) into LPS to strengthen chemical bonds and optimize lithium‐ion (Li ⁺ ) migration pathways in LPSQ electrolytes. Our results reveal that N and O facilitate the formation of PS ₃ Q polyanions, whereas F tends to exist as LiF. All LPSQ systems exhibit an extended electrochemical stability window than pristine LPS, substantially enhancing their compatibility with high‐voltage LiNi _0.8 Co _0.1 Mn _0.1 O ₂ (NCM811) cathodes. The strengthened chemical bonding environment further proves beneficial for both electronic and ionic conductivities, leading to superior performance in Li|LPSQ|Li symmetric batteries. Furthermore, by achieving an optimal balance between electronic and ionic conductivity, LPSN enables stable long‐term cycling for over 300 cycles at 1C in LiIn||NCM811 full battery, while maintaining high Coulombic efficiency and minimal interfacial degradation. These findings provide guidelines for dopant selection in SE design and offer perspectives on SE engineering aimed at enhancing the high‐voltage stability of ASSBs.