Na₂Ti₃O₇ 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 Na₂Ti₃O₇ 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.

中文翻译：

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了解和减轻钠离子电池阳极层状氧化物材料中的晶格塌陷降解


Na ₂ Ti ₃ O ₇ 由于钠离子电池的环保性和成本效益而引起了广泛关注。然而，它们有限的循环稳定性阻碍了它们的实际应用。在此，我们利用像差校正（扫描）透射阐明了 Na ₂ Ti ₃ O ₇ 阳极中异质相变引起的结构退化机制电子显微镜 (S)TEM 和原位 TEM。研究发现，不均匀分布的相变导致应变积累，促进微裂纹的生长，最终导致结构分解和电化学失效。受这种降解机制的启发，提出了纳米线，从而提高了结构稳定性，有效释放了晶格应变。这些发现加深了我们对插层电极材料中离子传输和降解机制的理解，同时强调了材料结构设计对于提高电极性能的重要性。