Unveiling Local Atomic Ordering of NbαV2‑αCT x MXenes for Lithium-Ion Storage

• Published in: Journal of physical chemistry. C 2024-12, Vol.128 (49), p.20782-20788
• Main Authors: Shi, Jialin, Wei, Shiqiang, Wang, Yixiu, Zhang, Pengjun, Cao, Yuyang, Guo, Xin, Zhang, Zijun, Xu, Hanchen, Wang, Changda, Chen, Shuangming, Song, Li
• Format: Article
• Language: English
• Subjects: C: Energy Conversion and Storage
• ISSN: 1932-7447; 1932-7455
• DOI: 10.1021/acs.jpcc.4c05886

The demand for innovative materials in energy storage and generation necessitates precise atomic-scale chemical control in nanomaterials. Double-transition metal (DTM) MXenes have expanded the chemical diversity of layered 2D materials, exhibiting unique physicochemical properties. However, the atomic ordering of DTMs and its impact on lithium storage performance require further investigation. Here, we report the synthesis of two-dimensional niobium–vanadium carbides (NbαV2‑αCT x ) by Lewis acid etching strategy, a previously unexplored class of DTM MXenes. By utilizing X-ray absorption fine structure (XAFS) spectra, we demonstrate that adjusting the Nb/V ratio enables tuning of the coordination number of Nb/V in NbαV2‑αCT x . As a result, the resulting Nb1.4V0.6CT x with enhanced local atomic ordering exhibited excellent rate performance and remarkable cycling stability. This study highlights the atomic-scale characterization of local structures using advanced X-ray spectroscopic techniques, expanding the diversity of the MXenes family.