First-principles calculation on the lithium storage properties of high-entropy MXene Ti3C2(N0.25O0.25F0.25S0.25)2

Abstract

Experimental studies had shown that a variety of surface functional groups exist simultaneously on the surface of Ti₃C₂T_x MXenes. However, current theoretical calculations on MXenes, used as anode materials for lithium-ion batteries, consider only one surface functional group, which fails to take into account the actual situation. In this study, combining the characteristics of high-entropy materials and two-dimensional MXene material, a model of MXene with multiple surface functional groups was constructed, and its electrochemical performance as an anode material for lithium-ion batteries was further explored. The Ti₃C₂(N_0.25O_0.25F_0.25S_0.25)₂ monolayer exhibited metallic properties. Meanwhile, Li atoms could be stably adsorbed on the surface and the diffusion energy barrier of Li on the surface was only 0.17 eV. First-principles calculation showed that Ti₃C₂(N_0.25O_0.25F_0.25S_0.25)₂ monolayer had good rate performance and low open-circuit voltage (1 V), corresponding to a lithium storage capacity of 385.38 mA h g⁻¹. The results of our work might inspire further studies on the Li storage performance of high-entropy MXenes experimentally and theoretically.