Tailoring the d-Band Center via Multi-Metal-Phosphorus d-p Orbital Hybridization in a High-Entropy Metal Phosphide to Enable Accelerated Sulfur Redox Kinetics.

Sluggish lithium polysulfide (LiPS) reduction kinetics and the shuttle effect lead to low active mass utilization and poor cycling stability, thereby seriously hampering the commercial application of Li-S batteries. Herein, a theoretically guided high-entropy phosphide (Fe0.74Co0.64Ni0.61Cu0.32Mo0.24P, FCNCMP-HEMP) nanoparticle is designed to enhance LiPS conversion. The electronic interaction among the S 3p orbitals of Sx 2- in LiPSs, the metal d orbitals, and the P 3p orbitals in FCNCMP-HEMP enables favorable catalytic activity for LiPS conversion. Impressively, FCNCMP-HEMP/C exhibits a higher electron transfer number and lower activation energy in solid-liquid-solid LiPS reduction reactions, indicating enhanced LiPS conversion kinetics. Specifically, Li-S cells with FCNCMP-HEMP/C@S cathodes deliver a high discharge capacity of 744 mAh g- 1 and an ultralow capacity decay of 0.014% per cycle over 2000 cycles at 5 C. Moreover, the assembled pouch cell with the FCNCMP-HEMP/C@S cathode shows a high energy density of 456 Wh kg- 1. This work opens a new pathway for designing high-entropy metal phosphides for high-performance Li-S batteries.