BC2N monolayers as promising anchoring materials for lithium-sulfur batteries: First-principles insights

Abstract

One of the major challenging issues in lithium-sulfur (Li-S) batteries is that the lithium polysulfides easily dissolve in the electrolyte and shuttle between anode and cathode. To overcome this problem, an ideal anchoring materials is urgent. In the current work, we explore the potential application of BC2N allotropes (approximated by Type-I and Type-II structures) as anchoring materials for Li-S batteries by using first-principles method with van der Waals interaction. Type-I is a direct-bandgap semiconductor, while type-II is semi-metallic due to inversion symmetry of its structure. They show remarkable but not too strong chemical interaction with S8 and Li2Sx clusters and enhanced electrical conductivity. In addition, the introduction of dopants and defects result in semiconductor-to-metal transition on type-I BC2N, and enhancement of binding energies and still keep intact Li2Sx clusters. Our findings demonstrate that defective and doped BC2N monolayers are promising anchoring materials for Li-S batteries.