Theoretical Investigation of the Structure-Property Correlation of MXenes as Anode Materials for Alkali Metal Ion Batteries

MXenes have been extensively explored as anode materials in Li, Na, and K ion batteries. However, the correlation between structural properties of MXenes and their electrochemical performances has not been fully understood. In the present study, the structural properties of five typical M3C2O2 (M = V, Ti, Nb, Hf, and Zr) and the adsorption and diffusion properties of Li, Na, and K atoms on them are studied in detail by using density functional theory calculations. Based on our calculated results, we found that different transition-metal-based M3C2O2 possessed highly distinct structural properties, which significantly influence the adsorption and diffusion behaviors of Li, Na, and K atoms on them. Thus, it can be concluded that the performance of M3C2O2 -based anode materials can be optimized by selecting an appropriate transition metal or applying biaxial strain to directly change the lattice constant of specific M3C2O2. Overall, our results will be helpful for efficient selection and design of effective M3C2O2 -based anode materials for Li, Na, and K ion batteries, which may also offer insight for selection and design of other two-dimensional material-based electrode materials in batteries.