Implanting MoS2 quantum dots on MgB2 nanosheets for lithium-sulfur batteries

As a new generation of high-efficiency energy storage devices, lithium-sulfur (Li-S) battery attract increasing attention. However, slow conversion kinetics of lithium polysulfides (LiPSs) and severe shuttle effect are bottlenecks. Developing efficient sulfur host materials to suppress the shuttling of LiPSs and accelerate their conversion kinetics is a general strategy to enhance the performance of Li-S batteries. Herein, MoS2 quantum dots (QDs)@MgB2 nanosheet was synthesized using a simple liquid-phase mixing method. The MoS2 QDs not only inhibit the stacking of MgB2 nanosheets but also expose more unsaturated metal active sites, which can effectively improve the adsorption of LiPSs, accelerate its catalytic conversion and suppress its shuttle effect. Moreover, MgB2 nanosheets can be used as polypropylene (PP) separator modifier. The battery using MoS2 QDs@MgB2 as the sulfur host material and MgB2@PP as the separator has high rate capability and excellent stability. In addition, the discharge-specific capacity shows a good application prospect.