Catalytic polysulfide conversion in lithium-sulfur batteries by platinum nanoparticles supported on carbonized microspheres

[Display omitted] •Synthetic strategy of accelerating conversion of LiPSs integrated with physical confinement.•Pt/CS composites with highly dispersed Pt nanoparticles (NPs) possess ultralow Pt weight ratio.•Regulation of LiPSs adsorption energy from charge transfer between Pt NPs and carbon matrix.•Experimental results confirm the catalysis of Pt NPs on conversion of LiPSs. Lithium-Sulfur (Li-S) battery has attracted extensive attentions in the field of energy storage due to its high theoretical specific capacity and low cost. However, the shuttle effect restricts its energy density and cycle performance, that hinders the industrialization process of Li-S battery. The introduction of catalysis in conversion of lithium polysulfides (LiPSs) is an effective strategy to suppress shuttle effect. Metal nanoparticles (NPs) are attractive catalysts due to excellent electrical conductivity and rapid electron transfer efficiency, therefore, metal NPs have great potential to be introduced in Li-S battery for studying and revealing elementary conversion reactions of LiPSs. Herein, based on the strategy of accelerating conversion of LiPSs integrated with physical confinement, we designed and synthesized Pt NPs supported on carbonized microspheres (Pt/CS composites). The catalytic conversion of LiPSs from charge transfer between Pt NPs and carbon matrix, combined with the strong physical confinement by surface pores of CS, result in upgraded electrochemical properties. It is demonstrated that the resulting Pt/CS cathode exhibits improved rate performance with specific capacity of 991.9 mAh g−1 at 0.1C, and maintains a fine cycling stability. This work provides a rational and facile route to construct metal supported catalytic electrode materials for Li-S battery.