Solvent effect on the storage behavior of metal ions on Ti3C2O2 surfaces

Abstract

MXenes, particularly Ti₃C₂O₂, are promising anode materials for metal-ion batteries due to their layered structure, high conductivity, and tunable surface chemistry. This study employs density functional theory (DFT) and the VASPsol implicit solvation model to investigate how varying dielectric constants influence the adsorption, diffusion, and storage behavior of Li⁺, Na⁺, and K⁺ ions on Ti₃C₂O₂ surfaces. The results show that increasing dielectric constant weakens ion–surface interactions, reduces diffusion barriers, and enhances ion mobility. K⁺ exhibits the lowest diffusion barrier, followed by Na⁺ and Li⁺. However, very high dielectric constants diminish stable ion adsorption, particularly for Li⁺, thus limiting storage capacity. These findings provide valuable insights into the optimization of MXene-based anodes for high-rate metal-ion batteries.