2D Carbon Phosphide for Trapping Sulfur in Rechargeable Li-S Batteries: Structure Design and Interfacial Chemistry

Rechargeable lithium-sulfur batteries (LiSBs) assembled with earth-abundant and safe Li anodes are less prone to form dendrites on the surface, and sulfur-containing cathodes offer considerable potential for achieving high energy densities. Nevertheless, suitable sulfur host materials and their interaction with electrolytes are at present key factors that retard the commercial introduction of these batteries. Here we propose a two-dimensional metallic carbon phosphorus framework, namely, 2D CP₃, as a promising sulfur host material for inhibiting the shuttle effect and improving electronic conductivity in high-performance Li-S batteries. The good electrical conductivity of CP₃ eliminates the insulating nature of most sulfur-based electrodes. The dissolution of lithium polysulfides (LiPSs) into the electrolyte is largely prevented by the strong interaction between CP₃ and LiPSs. In addition, the deposition of Li₂S on CP₃ facilitates the kinetics of the LiPS redox reaction. Therefore, the use of CP₃ for Li-S battery cathodes is expected to suppress the LiPS shuttle effect and to improve the overall performance, which is ideal for the practical application of Li-S batteries.