Immobilisation of sulphur on cathodes of lithium–sulphur batteries via B-doped atomic-layer carbon materials

Abstract

Developing new host materials for cathodes and exploring their binding mechanisms in lithium–sulphur batteries are crucial issues since the present host materials exhibit low sulphur entrapment properties, thus resulting in the rapid decay of overall performance. In this work, we systematically investigated B-doped atomic-layer carbon materials as the cathode hosts of lithium–sulphur batteries via density functional theory calculations. Based on the analysis of optimised molecular structures, binding energies and surface charge densities, we found that B-doping can help materials suppress the dissolution of sulphides during cycles, further improving the performance of lithium–sulphur batteries. Additionally, we concluded that the internal interactions among multiple Li₂S_n-adsorbed structures facilitate the capture of Li₂S_n. Furthermore, we found that B-doped graphdiyne is a promising host material since it exhibits a stronger attraction to Li₂S_n than other selected materials and an outstanding sulphur loading of ∼70 wt%.