Abstract
<jats:p>Metal fluorides suffer from sluggish electron/ion transport and severe interfacial parasitic reactions with sulfide solid electrolytes (SSEs), thereby deteriorating interfacial stability and limiting cycling lifespan. To mitigate these bottlenecks, oxygen doping is employed to modify insulating BiF3, yielding BiO0.67F1.66 composite. This strategy elevates the electronic and ionic conductivities of BiF3 to 7.28×10-3 μS/cm and 9.60 μS/cm, respectively. Meanwhile, the Li+ diffusion coefficient is improved by five orders of magnitude, reaching 10-11 cm2/s. Reduced Bader charge transfer verifies the alleviated interfacial side reactions and enhanced BiO0.67F1.66/SSE interfacial compatibility. The optimized BiO0.67F1.66 delivers a high reversible capacity of 202 mAh/g after 840 stable cycles, a superior rate capability of 210 mAh/g at 1C, and a low voltage hysteresis of only 162 mV when coupled with SSE. This work demonstrates that oxygen doping is a reliable strategy to resolve the sluggish kinetics and interfacial incompatibility of BiF3 cathodes toward SSEs, offering an effective route for developing high-energy-density solid-state lithium metal batteries.</jats:p>