Co‐Stabilization of High‐Entropy Oxides by Entropy and Polyanionic Units toward High‐Capacity Zero‐Strain Anodes for Advanced Lithium‐Ion Batteries

High-entropy oxides (HEOs) have attracted considerable attention as anode materials for lithium-ion batteries, owing to their entropy-driven structural stabilization. However, practical deployment is often limited by rapid capacity fading and irreversible phase transitions during cycling. To overcome these challenges, a phosphorus doping strategy is introduced that incorporates stable PO₄ ^3- groups into the HEO lattice, resulting in a novel zero-strain anode material, denoted as [P_x(LiCrMnFeCoZn)_1-x]₃O₄ (PHEO). The PHEO anode delivers a high specific capacity of 686.2 mAh g^-1 at 0.5 A g^-1, along with exceptional cycling stability exhibits exceptional cycling stability, retaining 116.4% of its capacity after 200 cycles and 149.6% after 1000 cycles at 2 A·g^-1. Structural and electrochemical analyses reveal that phosphorus doping effectively modulates the chemical states of multiple cations and enriches oxygen vacancy concentration, which reduces the bandgap and promotes pseudocapacitive charge storage. These effects, combined with the robust PO₄ tetrahedral framework and high-entropy effect, collectively contribute to enhanced specific capacity, improved structural integrity during cycling, and facilitated Li⁺ transport kinetics. This work offers a viable strategy for designing high-capacity, long-life HEO anodes with zero-strain characteristics for next-generation lithium-ion batteries.