Polar, catalytic, volume-tolerant CoSe2/carbon tubes for enhanced performance sulfur host in Li-S battery

The low sulfur utilization and notorious polysulfides shuttling of Li-S battery (LSBs) largely limit the practical implementation as an effective energy storage system. Herein, we designed a coaxial electrospinning process to prepare cobaltous selenide/carbon tube (CoSe2/CTs) with hollow tubular structures to hold sulfur activity for the cathode of LSBs. This CoSe2/CTs material with superior hollow tubular structures and high specific surface area is able to tolerate the sulfur volume expansion/contraction and make the intimate contact with sulfur at the micro level. Moreover, the uniformly dispersed CoSe2 on the CTs both as catalysts and trappers can significantly facilitate the reaction kinetics in the LSBs and chemically immobilize lithium polysulfides. In order to optimize the CoSe2/CTs/S cathode, we investigated the effects of the Co concentration and carbon tube porosities on batteries performance to achieve the satisfactory discharge specific capacity and a long duration at a high current density. We believe that our method can provide a significant strategy to prepare Co-based cathodes and enhance the performance of LSBs.