An in-situ electrodeposited cobalt selenide promotor for polysulfide management targeted stable Lithium–Sulfur batteries

Lithium–sulfur batteries (LSBs) have attracted much attention due to their high theoretical specific capacity, energy density and low cost. However, the commercial application of LSBs is hindered due to the lithium polysulfide (LiPS) shuttle as well as the sluggish reaction kinetics. Herein, cobalt selenide (Co 0.85 Se) nanowire arrays have been constructed on a carbon-modified separator by an in-situ electrodeposition technique without any other post-treatments such as coating with other ancillary materials. The introduced three-dimensional (3D) conductive carbon layer comprising of carbon nanotube (CNT) and acetylene black (AB) not only serves as the effective support for Co 0.85 Se (CS) but also builds a hierarchical structure to promote the e − transfer. The as-obtained CS-CNT/AB presents a strong anchoring effect on LiPSs and high electrocatalytic activity for sulfur reaction kinetics. As a result, the LSBs inserted with electrodeposition-enabled CS modified separator exhibit an outstanding rate capability (1560.4 mAh g −1 at 0.1 C) and relatively low capacity decay of only 0.068% per cycle over 500 cycles at 2.0 C. This study provides a promising strategy to realize the rational construction of high-efficiency and long-life LSBs.