Rational Design of 2D h-BAs Monolayer as Advanced Sulfur Host for High Energy Density Li-S Batteries

Abstract

The emergence of compact lithium-sulfur (Li-S) batteries with improved performances is becoming one of the most desirable aspects of future energy technologies. Beyond Li-ion batteries, Li-S is of great relevance to follow as it adapts to the specificity of each application. It is among the most suitable elements for high-performance energy storage systems, given its high theoretical capacity (1674 mA h g-1) and energy density (2600 W h kg-1) relative to Li-ion batteries (300 W h kg-1). Nevertheless, the high-cell polarization and the shuttle effect constitute an enormous challenge toward the concrete applications of Li-S batteries. In the framework of this work, density functional theory calculations have been carried out to analyze the potential of h-BAs nanosheets as a promising host material for Li-S batteries. Binding and electronic characteristics of lithium polysulfides (LiPSs) adsorbed on h-BAs surface have been explored. Reported findings highlight the potential of the h-BAs monolayer as a moderate host material, given that the binding energies of different LiPSs vary from 0.47 to 3.55 eV. More detailed analysis of the complex binding mechanisms is carried out by investigating the components of van der Waals physical/chemical interactions. The defected surface of the h-BAs monolayer has optimum binding energies with LiPSs for Li-S batteries. All these findings provide valuable insights into the binding and electronic characteristics of the h-BAs monolayer as a moderate host material for Li-S batteries.