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

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.