Modulating d–p Orbital Coupling via Gallium in High‐Entropy Metal Phosphides for Enhanced Lithium–Sulfur Batteries

Abstract To address the polysulfide shuttle effect and the sluggish kinetics of the multistep reactions in lithium–sulfur batteries, this study successfully synthesizes an optimized high‐entropy phosphide, Fe 0.5 Co 0.7 Ni 0.5 Cu 0.3 Ga 0.1 P (Ga‐HEP), by incorporating gallium. Density functional theory calculations indicate that gallium effectively strengthens the d–p orbital coupling within Ga‐HEP, thereby optimizing its electronic structure and enhancing charge‐transfer efficiency. Li 2 S deposition tests and cyclic voltammetry measurements further confirm that Ga‐HEP/PC exhibits a pronounced catalytic effect on the conversion of lithium polysulfides (LiPSs). Furthermore, in situ electrochemical impedance spectroscopy combined with relaxation time distribution analysis is employed to comprehensively investigate the complex electrochemical kinetic behavior and LiPS conversion mechanism of Ga‐HEP during charge–discharge processes. Notably, a battery equipped with a Ga‐HEP/PC@S cathode exhibits an excellent specific capacity of 1258.33 mAh g −1 at 0.2 C and ultra‐high cycling stability, with a specific decay rate of only 0.020% per cycle after 600 cycles at 5 C. Significantly, the Li–S pouch cell equipped with a Ga‐HEP/PC@S cathode delivers a high energy density of 403.61 Wh kg −1 .