Single-Crystallization of O3-Type Layered Oxide Cathode for Na-Ion Battery

作者：Qirui Liu, Wenhua Zuo, Zhefei Sun, Guifan Zeng, Yonglin Tang, Kai Fang, Dongyan Yu, Kang Zhang, Jiarui Li, Yuhao Hong, Tian Qiu, Niu Liu, Chuying Ouyang, Xianghui Xiao, Khalil Amine, Ziyang Ning, Qiaobao Zhang, Gui‐Liang Xu, Yu Qiao, Shi‐Gang Sun · 发表于：Chemistry of Materials · 年份：2025 · DOI：10.1021/acs.chemmater.5c01106 · 被引用次数：11 · 研究领域：Advancements in Battery Materials、Advanced Battery Technologies Research、Advanced Battery Materials and Technologies

The development of high-energy-density Na-ion batteries places significant demands on single-crystal layered oxide cathodes, especially for further high-voltage, solid-state battery scenarios. In the O3-type structure, due to the original sluggish Na ion diffusion kinetics (approximately 1 order of magnitude lower than that of Li-ion), and further hindrance against diffusion kinetics caused by single-crystal architecture, these inherent defects lead to the decline in the electrochemical performance. Herein, we demonstrated that the single crystallization of O3-type NaNi 1/3 Fe 1/3 Mn 1/3 O 2 cathode ( d 50 = 5.04 μm) aggravates surface-to-bulk phase inhomogeneity distribution, which is attributed to the uneven Na ions extraction. Moreover, the Na-depletion of the surface/shell region not only aggravates Na ion diffusion resistance but also leads to a higher valence state of transition-metal elements (e.g., Ni/Fe) near the surface of the single-crystal particle, which further compromises the cathode-electrolyte interface stability. Not limited to revealing the challenges, tuning the particle size and moderating quasi-single-crystal strategies have been proven to effectively mitigate the negative uneven distributions of Na ions, phases, and valence/oxidative states, resulting in efficient modification for single crystallization of Na-layered oxide cathodes.