Lithium-sulfur (Li-S) batteries are one of the most promising candidates for next-generation energy storage systems because of their high theoretical energy density. However, the shuttling behavior and sluggish conversion kinetics of lithium polysulfides (LiPSs) limit their practical application. Herein, B-doped MoS2 nanosheets are synthesized on carbon nanotubes (denoted as CNT@MoS2-B) to function as catalysts to boost the performance of Li-S batteries. The poor catalytic performance of the pristine MoS2 is revealed to be the result of unsuitable orbital orientation of the basal plane, which hinders the orbital overlap with sulfur species. B in CNT@MoS2-B is sp3 hybridized, and it has a vacant σ orbital perpendicular to the basal plane, which can maximize the head-on orbital overlap with S. The incorporation of B significantly increases the reactivity of MoS2 basal plane, which can facilitate the kinetics of Li2S formation and dissolution. With these merits, the S/CNT@MoS2-B cathodes deliver high rate capability and outstanding cycling stability, holding great promise for both scientific research and practical application. This work affords fresh insights for developing effective catalysts to accelerate LiPS conversion.
Keywords: electrocatalysis; lithium−sulfur batteries; orbital orientation; polysulfide redox reaction; shuttle effect.