BC6N as a promising sulfur host material for lithium-sulfur batteries.

High Adsorption energy between BC 6 NA and the substrates. [Display omitted] • Three types of B and N co-doped graphenes are studied as anchoring materials. • BC 6 NA exhibits excellent anchoring performance, which is superior to several similar doping systems. • BC 6 NA can improve electronic conductivity and reduce dissociation energy of the Sulfur cathode. Lithium-sulfur batteries (LSBs), which have six times the energy density of traditional lithium-ion batteries, are favorable candidates for the power system of next-generation electric vehicles, however, the sulfur cathode of lithium-sulfur batteries currently suffers from poor capacity retention and bad cycle performance. In this work, we study anchoring properties of B and N co-doped graphene by using density functional theory computations. Three doping configurations are considered and named as the adjacent (BC 6 NA), meta (BC 6 NM) and para (BC 6 NP) dopping, respectively. BC 6 NA has the best anchoring performance, as it has a strong absorption energy for the three clusters Li 2 S 4 (1.20 eV), Li 2 S 6 (1.51 eV) and Li 2 S 8 (1.81 eV), while both BC 6 NM and BC 6 NP have a relatively worse anchoring performance due to their weak physical adsorption, especially for the Li 2 S 4 cluster. Moreover, after adsorption the conductivity of the BC 6 NA is enhanced and the dissociation energy of the cluster is reduced, which further improve the performance of LSBs. This indicates that monolayer BC 6 NA is a promising sulfur host material for LSBs with a good anchoring performance. [ABSTRACT FROM AUTHOR]