First-Principles Investigation of Molybdenum Tetraboride Monolayer Interface for Improved Polysulfide Immobilization in Li-S Batteries

The shuttle effect of lithium polysulfides is a key challenge for Li–S batteries, leading to loss of sulfur, capacity fading and poor cycling stability. Herein, the MoB4 monolayer has been explored as a host cathode material through DFT calculations. The results show that MoB4 possesses good thermodynamic and dynamic stability, strong adsorption of sulfur and lithium polysulfides and effective polysulfide confinement to suppress the sulfur shuttling effect. In addition, MoB4 is catalytically active for Li2S conversion to facilitate the sulfur redox and improve the reaction kinetics. Good electronic conductivity, favorable conversion energetics and fast diffusion further facilitate sulfur utilization. The results demonstrate that MoB4 is a promising host material for high-performance Li–S batteries.