Synergistic adsorption and catalysis of polysulfides via d-p band center modulation in bimetallic phosphide heterostructures for high-performance Li-S batteries

The practical implementation of lithium‑sulfur (Li - S) batteries is critically hindered by the polysulfide shuttle effect and the sluggish conversion kinetics of lithium polysulfides (LiPSs). Herein, we design a freestanding interlayer comprising bimetallic phosphide nanoparticles embedded within interconnected porous carbon nanofibers (NiCoP@PCNF). In this architecture, the conductive PCNF skeleton functions as a physical barrier and facilitates rapid electron/ion transport, while the polar NiCoP nanoparticles serve as robust chemical anchors for LiPSs. Notably, density functional theory calculations and electrochemical analyses reveal that NiCoP acts as an efficient electrocatalyst by modulating its d-p band center, which optimizes electron transfer and substantially accelerates the liquid-solid conversion of LiPSs. Benefiting from this synergistic adsorption-catalysis effect, Li-S cells equipped with the NiCoP@PCNF interlayer deliver outstanding electrochemical performance, including a high initial capacity of 1652 mAh g −1 at 0.1C, an excellent rate capability of 1013 mAh g −1 at 2C, and exceptional cycling stability with a retained capacity of 757 mAh g −1 after 200 cycles at 3.0C. This work highlights a strategic design for multifunctional interlayers through the integration of conductive carbon frameworks with bimetallic phosphides, offering a promising pathway toward high-performance Li-S batteries.