Exploring the Electrocatalytic Performance and Strain Regulation Effects of Janus MoSO as a Promising Anchoring Material for Lithium–Sulfur Batteries

Developing efficient cathode host materials for inhibiting the shuttle effect and facilitating the redox conversion kinetics of polysulfides (PSs) is considered an important strategy to promote high-performance lithium-sulfur (Li-S) batteries. In this work, a Janus MoSO monolayer possessing a large intrinsic electric field has been chosen as the model to probe its potential as a cathode host material through density functional theory calculations. The O-side exhibits strong adsorption affinity and high catalytic conversion activity toward PSs, while the S-side still has insufficient trapping ability to eliminate the shuttle effect, even with the help of the intrinsic polarization within Janus structures. Both tensile and compressive strains can improve the immobilization ability of both sides of MoSO and enable the inactive S-side to achieve favorable adsorption strength toward PSs, successfully suppressing the shuttle effect. Combined with the prominent electronic conductivity, the appropriate adsorption ability, superior bidirectional catalytic activities of PS conversion, and rapid Li-ion diffusion, it is demonstrated that 10% tensile strain can endow both the O-side and S-side of Janus MoSO to be promising anchor and catalytic surfaces, significantly promoting the utilization efficiency of cathode host materials. The present merits of MoSO suggest that the inherent electric field of the Janus structure and strain engineering can be synergistically implemented to improve the performance of Li-S batteries.