A novel approach to effectively suppress the "polysulfide shuttle" in Li-S batteries is presented by designing a freestanding, three-dimensional graphene/1T MoS 2 (3DG/TM) heterostructure with highly efficient electrocatalysis properties for lithium polysulfides (LiPSs). The 3DG/TM heterostructure is constructed by few-layered graphene nanosheets sandwiched by hydrophilic, metallic, few-layered 1T MoS 2 nanosheets with abundant active sites. The porous 3D structure and the hydrophilic feature of 1T-MoS 2 are beneficial for electrolyte penetration and Li-ion transfer, and the high conductivities of both graphene and the 1T MoS 2 nanosheets facilitate electron transfer. These merits lead to a high electrocatalytic efficiency for LiPSs due to excellent ion/electron transfer and the presence of sufficient electrocatalytic active sites. Therefore, the cells with 3DG/TM exhibit outstanding electrochemical performance, with a high reversible discharge capacity of 1181 mA h g -1 and a capacity retention of 96.3% after 200 cycles. The electrocatalysis mechanism of LiPSs is further experimentally and theoretically revealed, which provides new insights and opportunities to develop advanced Li-S batteries with highly efficient electrocatalysts for LiPS conversion.
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© 2019 The Royal Society of Chemistry.