Borophene as Efficient Sulfur Hosts for Lithium–Sulfur Batteries: Suppressing Shuttle Effect and Improving Conductivity

Abstract

Stabilizing polysulfide shuttle while ensuring high sulfur loading holds the key to realizing high energy density of lithium–sulfur (Li–S) batteries. Herein we present our first-principles calculation on borophene as host of cathode in Li–S battery. The adsorption energies of sulfur cluster (S8) and its discharge products (Li2S8, Li2S6, Li2S4, Li2S2, and Li2S) on borophene are calculated. Our results indicate that borophene host can trap lithium polysulfides stably and effectively, which could avoid shuttle effect and improve the utilization of active material. The band structure of the adsorption structures shows that the borophene–sulfur cluster is metallic, while partial charge density proves that the conductivity is mainly due to the metallic borophene substrate. Such favorable electrical conductivity is helpful to the cathode charge/discharge processes. Therefore, borophene could be a promising host for S cathode due to its strong adsorption, high conductivity, and small deformation.