Suppressing Lattice Oxygen Release and Mitigating Mechanical Stress Buildup in Co-Free LiNiO<sub>2</sub> Cathodes.

Li, Yang; Wen, Lianghao; Qiu, Kai; Luo, Han; Xu, Cong; Zhang, Peng; Zhu, Gaolong; Tan, Tiening et al. · Nano Lett · 2025

basic_science · Level V

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Abstract

Cobalt-free LiNiO<sub>2</sub> (LNO) layered oxide cathodes are now positioned as a leading candidate for next-generation high-energy-density batteries, owing to their cost efficiency and ultra-high-capacity. Nevertheless, the coupled mechanical-electrochemical instability and thermally induced lattice oxygen evolution under extreme operating temperatures critically restrict their commercial deployment. Herein, we employ a high-valence W<sup>6+</sup> doping strategy to alleviate lattice stress in the LNO during high-temperature operation. Simultaneously, this modification markedly strengthens the anchoring of surface lattice oxygen, effectively inhibiting oxygen release from the bulk structure. The W-doped LNO cathode demonstrates an initial discharge capacity of 236.9 mAh g<sup>-1</sup> at 0.1 C under harsh 45 °C conditions. Remarkably, the modified electrode retains 77.6% of its capacity after 100 cycles, surpassing that of the pristine LNO, which suffers severe capacity degradation (65.4% retention) under identical testing protocols. This study presents critical strategic insights into the practical implementation of cobalt-free layered LNO cathodes under high-temperature operational environments.