In Situ Formation of a Hybrid Alloy‐Fluoride Interphase for Stable High‐Capacity Phosphorus Anodes

Phosphorus‐based anodes are promising candidates for next‐generation high‐energy‐density lithium‐ion batteries owing to their high theoretical capacity. However, their practical application is severely limited by drastic volume variation and unstable solid electrolyte interphase (SEI) chemistry. Achieving both mechanical robustness and rapid ion transport within the SEI remains a long‐standing challenge. Herein, trace SbF 3 is doped into the phosphorus‐carbon (P/C) composites through a facile ball‐milling. Taking advantage of the SbF 3 preferential reduction over phosphorus, a hybrid interphase enriched with Li 3 Sb and LiF is in situ formed during initial lithiation. The hybrid interphase effectively suppresses the dissolution and shuttling of polyphosphides, which also integrates fast ionic/electronic transport with enhanced mechanical rigidity, thereby accelerating reaction kinetics. The synergetic effect endows the P/C‐SbF 3 anode with a high retained capacity of 970.10 mAh g −1 after 500 cycles at 1 A g −1 and a superior rate capability of 893.84 mAh g −1 at 15 A g −1 . When paired with an NCM811 cathode, the full cell retains 80.25% of its capacity after 400 cycles at 1 C. The single‐layer pouch full cell further confirms the practical feasibility. This work highlights in situ formed hybrid interphase engineering for overcoming the stability‐transport trade‐off in high‐capacity alloying anodes.