The design and preparation of the composite with layered spherical structure for Li-S battery

Abstract

The composite of polythiophene/sulfur/Ketjen black with the layered spherical structure was designed and prepared to reduce the loss of active material and weaken the “shuttle effect” of polysulfides in Li-S battery. Ketjen black particle, which serves as conductive carbon core, was firstly coated by sulfur layer, and then sulfur/carbon particle was wrapped by polythiophene layer through in situ polymerization procedure. The structure, conductive properties, and electrochemical performance of composites with different polymerization times were investigated. Results show that the 10-h composite presents both the highest electronic conductivity of 4.51 × 10−3 S cm−1 and the highest ionic conductivity of 8.72 × 10−12 cm2 s−1. Moreover, it also exhibits the best electrochemical performance as the cathode material in Li-S battery. The conducting polythiophene with lithium storage ability contributes to improve the electrochemical activity of sulfur. Besides, due to its coating function, the dissolution loss and the “shuttle effect” of polysulfides are suppressed to a certain extent.