Wyckoff Kira E, Zohar Arava, Li Tianyu, Zhou Yucheng, Kautzsch Linus, Wang Welton, Kepper Ananya, Patterson Ashlea R, Mandujano H Cein, Koirala Krishna Prasad, Kallistova Anna, Xu Wenqian, Liu Jue, Pilon Laurent, Cheetham Anthony K, Seshadri Ram
Materials Department and Materials Research Laboratory University of California, Santa Barbara, California 93106, United States.
Mechanical and Aerospace Engineering Department Henry Samueli School of Engineering and Applied Science, University of California, Los Angeles, California 90095, United States.
J Am Chem Soc. 2025 Sep 17;147(37):33432-33441. doi: 10.1021/jacs.5c06578. Epub 2025 Sep 2.
Oxides of Nb with Wadsley-Roth shear structures comprise a family of stable, high-rate anode materials for Li-ion batteries. A particular pair of them offers the unusual opportunity to test how important metallic conduction of the starting electrode is for electrode performance. The selected pair of compounds with similar 4 × 3 Wadsley-Roth block structures are insulating TiNbO and metallic NbO. A combination of diffraction, electrochemistry, magnetic measurements, and entropic potential measurements is employed to establish key findings for these two anode materials. We find that starting with a metallic oxide is not especially advantageous over a comparable material that readily transitions into a metallic state upon lithiation. Second, the rate performance appears to be dictated by ion mobility, and atomic Ti/Nb disorder in TiNbO contributes to improved capacity retention at high rates by suppressing Li-ion ordering. However, subtle details in the nature of redox processes make NbO a slightly better electrode material for long-term cycling at slower rates.
具有瓦兹利-罗斯剪切结构的铌氧化物是一类用于锂离子电池的稳定、高倍率阳极材料。其中特定的一对材料提供了一个非同寻常的机会，来测试起始电极的金属导电性对电极性能有多重要。所选择的具有相似4×3瓦兹利-罗斯块结构的一对化合物是绝缘的TiNbO和金属性的NbO。结合衍射、电化学、磁性测量和熵势测量来确定这两种阳极材料的关键发现。我们发现，从金属氧化物开始并不比锂化时容易转变为金属态的类似材料特别有优势。其次，倍率性能似乎由离子迁移率决定，并且TiNbO中的原子Ti/Nb无序通过抑制锂离子有序排列有助于在高倍率下提高容量保持率。然而，氧化还原过程性质中的细微细节使NbO成为在较低倍率下长期循环的稍好的电极材料。
