Multifunctional ultrasmall-MoS2/graphene composites for high sulfur loading Li–S batteries

Abstract

Combination of sulfur hosts with high sulfur loading content and multifunctional additives which can anchor lithium polysulfides and exhibit catalytic properties for polysulfides is an effective way to improve the performance of Li–S batteries and make them more competitive. Herein, we utilize high specific surface area N-doped graphene materials (NGM) as sulfur hosts with high sulfur loading contents reaching 92 wt%. Meanwhile, small amounts of ultrasmall-MoS₂/graphene composites (MoS₂–G) which can act as multifunctional additives to anchor lithium polysulfides and promote their conversion are added into the cathode. Moreover, the ultrasmall-MoS₂ nanoparticles with (100) surfaces can anchor Li₂S₆ strongly by forming Mo–S bonds with a binding energy of 4.19 eV. With the synergistic effects of the NGM sulfur host and the MoS₂–G multifunctional additives, the Li–S batteries displayed stable cycling performance and good rate capability at high sulfur loading content.