Transition Metal-Doped Boron Phosphide Monolayer in Lithium–Sulfur Batteries with Anchoring Ability and Catalytic Performance: A First-Principles Study

The practical application of lithium–sulfur (Li–S) batteries is still hindered by some challenges, including sluggish transformation kinetics, the notorious shuttle effect, and the low utilization ratio of sulfur. Two-dimensional (2D) polar materials binding single atoms for catalysis are a promising approach to overcoming these obstacles. Herein, transition metal atom (Sc, Ti, and V)-doped hexagonal boron phosphide monolayers (TM-BP) are explored to reveal their potential as an anchoring and catalytic material using first-principles calculations. S8/Li2Sn molecules can be anchored on TM-BP monolayers, and the solvent environment has only little effect on the anchoring strength. Importantly, the Sc-BP monolayer exhibits suitable catalytic activity through inhibiting the conversion of soluble Li2S8 to Li2S6, which can effectively suppress the accumulation of soluble lithium polysulfides in the electrolyte. The Ti/V-BP monolayer can improve the rate performance due to the fast reaction kinetics. Moreover, the decomposition of Li2S on monolayers shows low energy barrier, indicating that TM-BP can increase the utilization of sulfur and cycling performance of the Li–S battery. According to our results, TM-BP monolayers have the ability of addressing the obstacle in Li–S batteries due to their suitable anchoring performance and catalytic properties. They are a promising modification material for Li–S batteries.