Proposing the prospects of Ti3CN transition metal carbides (MXenes) as anodes of Li-ion batteries: a DFT study

Abstract

A two-dimensional (2D) transition metal carbonitride (MXenes) with a formula of Ti₃CN as an anode of a lithium-ion battery (LIB) has been proposed in this work. The mechanism of Li⁺ adsorption and diffusion on the surface of Ti₃CN and Ti₃CNT₂ (T = F, O, and OH functional groups) was studied to estimate the potential application of Ti₃CN as an anode material by density functional theory (DFT) and DFT+U computations. For Ti₃CNT₂ (T = O, F, OH), the value of Li diffusion barriers is from 0.2 eV to 0.3 eV. On the basis of our results, we can know that Li prefers adsorption on the nitrogen side for Ti₃CN in the absence of functional groups and tends to adsorb on the carbon side for Ti₃CNT₂ (T = O, F, OH). This phenomenon can be explained by Bader charge population analysis. For Ti₃CNF₂, Li–F formed a six-membered ring with increasing Li concentration, thereby making the system more stable. This work contributes to offering perspectives for carbonitride systems (MXenes) as LIB anodes.