Cheng Lixun, Luo Xiaonan, Ge Binghui
Information Materials and Intelligent Sensing Laboratory of Anhui Province, Leibniz International Joint Research Center of Materials Sciences of Anhui Province, Institutes of Physical Science and Information Technology, Anhui University, Hefei 230601, China.
Contemporary Amperex Technology Co Ltd, No.2, Xingang Road, Zhangwan Town, Jiaocheng District, Ningde, Fujian 352000, China.
ACS Appl Mater Interfaces. 2024 Jul 10;16(27):35006-35012. doi: 10.1021/acsami.4c05433. Epub 2024 Jun 27.
NaTiO has attracted significant attention due to its ecofriendliness and cost-effectiveness for sodium-ion batteries. However, their limited cycling stability hampers their practical applications. Herein, we elucidate a mechanism of structural degradation caused by the heterogeneous phase transition in the NaTiO anode using aberration-corrected (scanning) transmission electron microscopy (S)TEM and in situ TEM. It is found that the unevenly distributed phase transition results in the accumulation of strain, which promotes the growth of microcracks and eventually leads to structural decomposition and electrochemical failure. Motivated by this degradation mechanism, nanowires were proposed, and the structural stability is thus improved with the lattice strain effectively released. These findings deepen our understanding of ion transport and degradation mechanisms in intercalated layered electrode materials while emphasizing the significance of the material structure engineered for improving electrode performance.
由于其对钠离子电池的环境友好性和成本效益，NaTiO受到了广泛关注。然而，它们有限的循环稳定性阻碍了其实际应用。在此，我们使用像差校正（扫描）透射电子显微镜（S）TEM和原位TEM阐明了NaTiO阳极中由非均相相变引起的结构降解机制。研究发现，不均匀分布的相变导致应变积累，这促进了微裂纹的生长，并最终导致结构分解和电化学失效。受这种降解机制的启发，人们提出了纳米线，从而有效地释放了晶格应变，提高了结构稳定性。这些发现加深了我们对插层层状电极材料中离子传输和降解机制的理解，同时强调了为提高电极性能而设计的材料结构的重要性。
