Two-dimensional materials such as MXenes are being actively considered by the community for energy storage applications. Here, we employ Density Functional Theory (DFT) to model O and S terminated Zr₂C MXenes. We find that the most energetically favourable positions for the termination atoms to sit are on top of the second-layer Zr atoms, in agreement with previous studies. Finally, arbitrarily placing a Li-ion on the surface of the MXenes, we apply the Bond Valence Sum (BVS) model to calculate Bond Valence Site Energies (BVSE). We show that BVS is a good substitute for DFT particularly for diffusion pathways, as it yields much faster results and with good accuracy, with the added advantage of not needing exact positions for the atoms. BVS can, therefore, be used as a quick filter when searching for low migration barriers in MXenes and two-dimensional materials.

社区正在积极考虑将 MXenes 等二维材料用于储能应用。在这里，我们采用密度泛函理论 (DFT) 对 O 和 S 端接 Zr ₂进行建模C MXenes。我们发现终止原子在能量上最有利的位置位于第二层 Zr 原子的顶部，这与之前的研究一致。最后，在 MXenes 表面任意放置锂离子，我们应用键价总和 (BVS) 模型来计算键价位点能量 (BVSE)。我们表明 BVS 是 DFT 的良好替代品，特别是对于扩散路径，因为它产生更快的结果和良好的准确性，并且具有不需要原子精确位置的额外优势。因此，在 MXenes 和二维材料中寻找低迁移障碍时，BVS 可以用作快速过滤器。