Janus-type monolayer M2SSe (M = Ga, In, B, and al) as sulfur host materials for lithium-sulfur batteries: A first-principles study

Lithium-sulfur batteries (LSBs) are notable for their outstanding energy density , economic viability, and environmental friendliness, positioning them as a leading option for future energy storage solutions. Nevertheless, the insulation of sulfur, the shuttle effect, and the sluggish redox kinetics limit their application. Hence, finding a suitable sulfur host material is critical to improve the performance of LSBs. In this work, the comprehensive calculations of adsorption configurations, electronic properties, and Gibbs free energy during catalytic processes are conducted to reveal the unique advantages of Janus-type monolayer M 2 SSe (M = Ga, In, B, and Al) as a potential sulfur host material. The calculated results indicate that M 2 SSe monolayers exhibit semiconducting properties and effectively adsorb soluble lithium polysulfides , thereby enhancing the conductivity and response speed of LSBs, and suppressing the shuttle effect. Moreover, M 2 SSe exhibits bifunctional electrocatalytic ability, improving the conversion of lithium polysulfide during charging and discharging, thus effectively accelerating the redox kinetics of LSBs. Among the Janus-type M 2 SSe series, the Se-side of In 2 SSe exhibits the most promising characteristics. This study indicates that Janus-type monolayer M 2 SSe (M = Ga, In, B, and Al) effectively serves as a sulfur host material for LSBs, overcoming critical challenges and improving overall performance. • Proposed Janus-type M 2 SSe monolayers as sulfur host materials for Li–S batteries. • Dual-functional catalytic activity for SRR and Li₂S decomposition is demonstrated. • Se-side of In₂SSe achieves optimal adsorption strength and catalytic efficiency.