Co-W bimetallic carbides as sulfur host for high-performance lithium–sulfur batteries

Due to the low conductivity of sulfur and the dissolution of polysulfides, the application of lithium–sulfur (Li–S) batteries have encountered certain resistance. Increasing conductivity and introducing polarity into the sulfur host can effectively overcome these long-standing problems. Herein, we first prepared Co3W3C@ C@CNTs/S material and used it in the cathode of lithium–sulfur batteries. Carbon nanotubes treated with acidification have good dispersibility in aqueous solution, good adsorption on positively charged metal ions due to abundant oxygen-containing functional groups on the surface. After carbonization treatment, Co3W3C will be firmly anchored on the surface of carbon nanotubes, which is conducive to improving the electrical conductivity and stability of its own materials. Polar Co3W3C can form a strong interaction with polysulfide intermediates, effectively inhibiting its shuttle effect, improving the utilization of sulfur cathode electrodes, and keeping the capacity and cycle stability. The Co3W3C@C@CNTs/S electrode material has a capacity of 1093 mA h g−1 at 0.1 A g−1 and 482 mA h g−1 at 5 A g−1. Even after 500 cycles of 2 A g−1, the capacity of each cycle is only reduced by 0.08%. The excellent stability of this material can provide a new idea for the future development of lithium–sulfur batteries.