Interlayer-expanded MoSe2 nanotubes as multifunctional separator coating for high-performance lithium-sulfur battery

Abstract

Lithium-sulfur battery is regarded as one of the most promising energy storage devices. However, its cycling performance is severely impeded by the sluggish polysulfide conversion kinetics and intractable polysulfide shuttling. Herein, multifunctional interlayer-expanded MoSe2 nanotubes are fabricated and coated on the Celgard separator, which has exhibited a great efficacy in trapping polysulfides and catalyzing sulfur conversion. The hierarchical structure of MoSe2 nanotubes and their polar nature affords sufficient catalytic sites and exhibits strong chemisorptivity for polysulfide conversion. The enlarged interlayer distance is much more favorable for a low barrier Li+ ions transportation. It is found that the batteries with the interlayer-expanded MoSe2 coating separator delivered enhanced rate performances and cycling capability. By assembling with just a simple sulfur/carbon cathode, the battery exhibits a high reversible capacity of 952 mA h g−1 at 0.2 C, remarkable cycling stability with a low-capacity fading rate of 0.13 % over 150 cycles at 1 C, and an excellent rate performance of up to 413 mA h g−1 at 2 C. These results reveal that the interlayer-expanded MoSe2 separator coating is effective to promote sulfur conversion as well as suppress the shuttle effect, which may be beneficial for developing future high-performance lithium-sulfur batteries.