Computational study on two-dimensional transition metal borides for enhanced lithium-sulfur battery performance: Insights on anchoring, catalytic activity, and solvation effects.

The controlled modulation of surface functional groups, in conjunction with the intrinsic structural characteristics of MXene materials, shows great potential in alleviating the shuttle effect and improving the sluggish reaction kinetics in lithium-sulfur batteries (LSBs). This study delves into the impact of surface functional groups (T = O, S, F, and Cl) on VB MBene concerning sulfur immobilization and kinetic catalytic properties through meticulous first-principles calculations. The results reveal that the establishment of T-Li bonds within VBT (T = O, S, F, and Cl) enhances the adsorption of lithium polysulfides (LiPSs). Moreover, the robust interactions between the T_p and V_d orbitals play a pivotal role in strengthening the T-V bond and reducing the energy barrier for LiS decomposition. Comparative analyses underscore the outstanding performance of VBO, showcasing a moderate adsorption strength for LiPSs, remarkable electrocatalytic activity for LiS decomposition (with an energy barrier of 0.42 eV), and a low LiS diffusion barrier (0.16 eV). These attributes facilitate effective anchoring and expedite reaction kinetics for LiPSs. Furthermore, the influences of solvation and temperature were found to have substantial impacts on the anchoring capability of VBT except for VBO. This study establishes a critical theoretical framework and serves as a valuable reference for advancing MBene materials as cathodes for LSBs.