Jian Li

High‐entropy oxides represent a paradigm shift in sodium‐ion battery cathodes by utilizing entropy‐driven structural stabilization to address the intrinsic challenges of lattice strain and sluggish ion kinetics. However, conventional high‐entropy oxides face challenges in synthesis complexity and insufficient mechanistic insights into strain‐kinetics coupling. Here, a high‐entropy O3‐type layered oxide, Na _0.9 Ni _0.2 Co _0.2 Fe _0.2 Mn _0.2 Zn _0.05 Cu _0.05 Ti _0.1 O ₂ (NNCFMZCT), is proposed featuring seven transition metals in a single crystallographic site, to synergistically optimize Na⁺ diffusion and structural resilience. Density functional theory calculations reveal that configurational disorder mitigates anisotropic lattice contraction during O/P phase transitions, while X‐ray photoelectron spectroscopy and in situ X‐ray diffraction confirm stable TMO₆ octahedra and suppressed irreversible phase transitions. The NNCFMZCT cathode delivers a high reversible capacity (>130 mAh g ⁻¹ at 10 mA g ⁻¹ ), exceptional cycling stability (82.9% retention over 300 cycles at 500 mA g ⁻¹ ), and superior rate capability (>110 mAh g ⁻¹ at 1000 mA g ⁻¹ ) within 2.0–4.0 V. When paired with commercial hard carbon in ampere‐hour‐level cylindrical cells, the full cell achieves 84% capacity retention after 200 cycles. This work demonstrates scalable viability for grid storage by establishing a universal strain‐kinetics coupling strategy, which advances the rational design of entropy‐stabilized cathodes for sustainable energy systems.

High‐entropy oxides, with their diverse compositions and entropy‐stabilized structures, have emerged as promising candidates for sodium‐ion battery cathodes. However, phase transitions in these materials are highly sensitive to the specific transition metal composition, and effective design strategies remain underdeveloped. Herein, a six‐element high‐entropy layered oxide cathode, O3‐Na _0.9 Ni _0.3 Fe _0.1 Zn _0.1 Cu _0.05 Mn _0.3 Ti _0.15 O ₂ , is reported in which the incorporation of Zn and Cu not only alters the electronic structure but also affects the formation angle of desired OP2 phase. By fine‐tuning Zn/Cu ratio, we optimize the phase transition behavior of high‐entropy layered oxides, significantly enhancing structural stability and electrochemical performance. This material delivers a high specific capacity of 146.9 mAh g ⁻¹ with superior cycling performance (80.4% capacity retention after 500 cycles). Furthermore, utilizing the as‐prepared cathode and commercial hard carbon anode, 1.1 Ah cylindrical cells successfully demonstrated high initial Coulombic efficiency of 92% and rapid charge and discharge rates up to 5C, retaining 93.6% of the capacity. Notably, these cylindrical cells exhibit excellent cycling stability with capacity retention of 86% after 300 cycles.