Ultrathin SnS2 nanosheets as robust polysulfides immobilizers for high performance lithium-sulfur batteries

Abstract

Ultrathin SnS2 nanosheets modified sulfur/carbon (S/C-SnS2) composites were synthesized through a facile method by mixing sublimed sulfur, Ketjen Black and ultrathin SnS2 nanosheets. The ultrathin SnS2 nanosheets can provide remarkable binding strength, large surface area and fast charge transfer, therefore leading to favorable chemical interaction with polysulfides in Li-S batteries. Accompanied with the synergistic effects between physical confinement of porous carbon and chemical interactions of SnS2, S/C-SnS2 composites with different mass ratio of ultrathin SnS2 nanosheets and C show much improved electrochemical properties. Among them, S/C-SnS2 composite with 10wt% of ultrathin SnS2 nanosheets and 75wt% of sulfur maintains superior long term cycling capacities of 800mAhg−1 at 0.5C after 300 cycles and 540mAhg−1 at 2C after 700 cycles.