Wyckoff Kira E, Kaufman Jonas L, Baek Sun Woong, Dolle Christian, Zak Joshua J, Bienz Jadon, Kautzsch Linus, Vincent Rebecca C, Zohar Arava, See Kimberly A, Eggeler Yolita M, Pilon Laurent, Van der Ven Anton, Seshadri Ram
Materials Department and Materials Research Laboratory, University of California Santa Barbara, Santa Barbara, California 93106, United States.
Mechanical and Aerospace Engineering Department, Henry Samueli School of Engineering and Applied Science, University of California Los Angeles, Los Angeles, California 90095, United States.
J Am Chem Soc. 2022 Apr 6;144(13):5841-5854. doi: 10.1021/jacs.1c12070. Epub 2022 Mar 25.
Electrode materials for Li-ion batteries require optimization along several disparate axes related to cost, performance, and sustainability. One of the important performance axes is the ability to retain structural integrity though cycles of charge/discharge. Metal-metal bonding is a distinct feature of some refractory metal oxides that has been largely underutilized in electrochemical energy storage, but that could potentially impact structural integrity. Here LiScMoO, a compound containing triangular clusters of metal-metal bonded Mo atoms, is studied as a potential anode material in Li-ion batteries. Electrons inserted though lithiation are localized across rigid Mo triangles (rather than on individual metal ions), resulting in minimal structural change as suggested by diffraction. The unusual chemical bonding allows this compound to be cycled with Mo atoms below a formally +4 valence state, resulting in an acceptable voltage regime that is appropriate for an anode material. Several characterization methods including potentiometric entropy measurements indicate two-phase regions, which are attributed through extensive first-principles modeling to Li ordering. This study of LiScMoO provides valuable insights for design principles for structural motifs that stably and reversibly permit Li (de)insertion.
锂离子电池的电极材料需要在与成本、性能和可持续性相关的几个不同方面进行优化。重要的性能方面之一是在充放电循环中保持结构完整性的能力。金属-金属键是一些难熔金属氧化物的显著特征，在电化学储能中很大程度上未得到充分利用，但可能会影响结构完整性。在这里，LiScMoO，一种含有金属-金属键合的Mo原子三角簇的化合物，被研究作为锂离子电池中的潜在阳极材料。通过锂化插入的电子定域在刚性的Mo三角形上（而不是单个金属离子上），如衍射所示，结构变化最小。这种不寻常的化学键合使得该化合物能够在Mo原子处于形式上低于+4价态的情况下循环，从而产生适合阳极材料的可接受电压范围。包括电位熵测量在内的几种表征方法表明存在两相区域，通过广泛的第一性原理建模将其归因于Li有序化。对LiScMoO的这项研究为稳定且可逆地允许Li嵌入/脱出的结构基序的设计原则提供了有价值的见解。
