Soft template synthesis of acetylene black/manganese dioxide nanosheets composites as efficient sulfur hosts for lithium-sulfur batteries

摘要

Manganese dioxide (MnO2)-based nanomaterials can be used as sulfur host, improving the cycle stability by inhibiting the shuttle effects of polysulfide through chemisorption with the polar host. In this work, we design a novel soft template synthesis of acetylene black and MnO2 nanosheets (AB/MnO2) composites by simple and cost-effective methodology. The AB/MnO2 was used as a highly efficient sulfur host for advanced lithium-sulfur batteries. The cheap and highly conductive AB facilitates fast electron transport. The polar host, MnO2 nanosheets, provides chemical interactions and efficiently impedes the dissolution of polysulfide. Accordingly, the cathodes AB/MnO2-S (4:1) and AB/MnO2-S (1:1) with 67 and 70 wt% sulfur content deliver the initial discharge specific capacity of 1326 and 1113 mA h g(-1) at the current density of 837.5 mA g(-1) (0.5 C), respectively. Particularly, the AB/MnO2-S (1:1) cathode shows the most stable coulombic efficiency and cyclability compared with AB/S cathode after 200 cycles. In addition, the AB/MnO2-S (4:1) cathode exhibits a capacity of 1071 mA h g(-1) at the current density of 1675 mA g(-1) (1 C). Along with this green and cost-effective protocol of synthesis, we expect that the AB/MnO2 composites have potential application in advanced Li-S batteries.