Institute of Molecular Sciences and Engineering, Institute of Frontier and Interdisciplinary Science, Shandong University, Qingdao, Shandong, 266237, China.
Small. 2023 Jun;19(26):e2300914. doi: 10.1002/smll.202300914. Epub 2023 Mar 22.
Previously, heat treatment was the only feasible route for tuning the crystal phases of niobium pentoxide (Nb O ). With the use of Nb CT MXene precursors, the first case of phase tuning of Nb O in the low-temperature hydrothermal synthesis using sulfuric acid regulating agents is presented. By varying the amount of the agent, four pure-phase Nb O crystals and mixed phases in-between are obtained. The required amount is found to be related to the H-covered surface energy calculated based on density functional theory. Overall, MXene-derived B-phase Nb O is of particular interest due to its exceptionally high capacities as lithium-ion battery anodes, which are three times higher than the routine synthesized one. Oxygen vacancies induced by crystallographic shear would be responsible for the extraordinary performance. The proposed phase tuning strategy encourages the prudent synthesis of difficult-to-obtain crystal phases.
先前，热处理是调谐五氧化二铌（NbO ）晶体相的唯一可行途径。利用 Nb CT MXene 前体，首次在使用硫酸调节剂的低温水热合成中实现了 NbO 的相调谐。通过改变调节剂的用量，可以获得四种纯相 NbO 晶体和介于两者之间的混合相。所需的用量与基于密度泛函理论计算的 H 覆盖表面能有关。总的来说，由于作为锂离子电池负极的容量异常高，MXene 衍生的 B 相 NbO 特别有趣，其容量是常规合成的三倍。由晶体剪切引起的氧空位将是非凡性能的原因。所提出的调相策略鼓励审慎合成难以获得的晶体相。
