Toward high-performance LiS batteries: phosphorus-doped vanadium nitride in interconnected carbon frameworks for inhibiting polysulfide shuttle.

The "shuttle effect" observed in lithium‑sulfur (LiS) batteries, originating from conversion of Li2S4 to Li2S during the sulfur reduction reaction, severely limits their electrochemical performance. Here, a phosphorus-doped vanadium nitride anchored on an interconnected three-dimensional porous carbon framework co-doped with nitrogen and phosphorus (P-VN@NPC) is rationally designed as a catalytic sulfur host to regulate polysulfide conversion. The P-VN@NPC cathode maintains a discharge capacity of 624 mAh·g-1 at 5C under a high sulfur loading of 4.53 mg·cm-2 and preserves 75.91% of its capacity after 130 cycles. The high performance of P-VN@NPC is ascribed to the synergistic effect of the interconnected three-dimensional porous carbon framework and electronically regulated P-doped VN, which simultaneously enhance polysulfide adsorption and accelerate conversion kinetics. Theoretical and experimental results demonstrate that P-VN@NPC promotes the liquid-solid conversion of Li2S4 to Li2S through optimizing polysulfide adsorption and reducing the kinetic barriers associated with sulfur redox reactions. This work demonstrates that heteroatom doping of metal nitrides within three-dimensional porous carbon frameworks enhances polysulfide anchoring and catalytic conversion for advanced LiS batteries.