Saber Muna, Van der Ven Anton
Department of Chemical Engineering, University of California, Santa Barbara, Santa Barbara, California 93106, United States.
Materials Department, University of California, Santa Barbara, Santa Barbara, California 93106, United States.
Inorg Chem. 2024 Jun 17;63(24):11041-11052. doi: 10.1021/acs.inorgchem.4c00603. Epub 2024 Jun 3.
The Wadsley-Roth family of transition metal oxide phases are a promising class of anode materials for Li-ion batteries due to their open crystal structures and their ability to intercalate Li at high rates. Unfortunately, most early transition metal oxides that adopt a Wadsley-Roth crystal structure intercalate Li at voltages that are too high for most battery applications. First-principles electronic structure calculations are performed to elucidate redox mechanisms in Wadsley-Roth phases with the aim of determining how they depend on crystal structure. A comparative study of two very distinct polymorphs of NbO reveal two redox mechanisms: (i) an atom-centered redox mechanism at early stages of Li intercalation and (ii) a redox mechanism at intermediate to high Li concentrations involving the bonding orbitals of metal-metal dimers formed by edge-sharing Nb cations. Our study motivates several design principles to guide the development of new Wadsley-Roth phases with superior electrochemical properties.
瓦兹利-罗斯（Wadsley-Roth）过渡金属氧化物相由于其开放的晶体结构以及能够高速嵌入锂的能力，是一类很有前景的锂离子电池负极材料。不幸的是，大多数采用瓦兹利-罗斯晶体结构的早期过渡金属氧化物在嵌入锂时的电压对于大多数电池应用来说过高。进行第一性原理电子结构计算以阐明瓦兹利-罗斯相中氧化还原机制，目的是确定它们如何依赖于晶体结构。对两种截然不同的NbO多晶型物的比较研究揭示了两种氧化还原机制：（i）锂嵌入早期以原子为中心的氧化还原机制，以及（ii）锂浓度处于中高时涉及由边共享Nb阳离子形成的金属-金属二聚体的成键轨道的氧化还原机制。我们的研究提出了几个设计原则，以指导具有优异电化学性能的新型瓦兹利-罗斯相的开发。
