Constructing the Mo2C/C heterojunction to achieve high performance lithium-sulfur batteries
Lithium-sulfur batteries are highly valued for their outstanding theoretical energy and high energy density,but the severe shuttle effect of lithium polysulfides(LiPSs)hinders their commercialization.Combining carbon materials with high specific surface area and catalysts that accelerate the conversion of lithium polysulfides is considered an effective strategy.Nevertheless,there is still a lack of in-depth investigation on constructing heterojunction between carbon materials and catalysts,and investigating their effects on the performance of lithium-sulfur batteries.In this study,Mo2C was prepared by annealing calcination method and subsequently coated onto a microporous polypropylene membrane in conjunction with porous carbon to produce a Mo2C/C@PP composite membrane.The electrochemical performance test results show that the Mo2C/C heterojunction-rich composite effectively captures soluble polysulfides,optimizes the solid-liquid interface of the electrolyte/separator,inhibits the shuttle of polysulfides,enhances the utilization of sulfur cathode,promotes uniform deposition of lithium,and improve the rate performance.The composite exhibits a high initial specific capacity of 773.3 mA·h·g-1 at a 1 C rate,retaining 615.1 mA·h·g-1 after 500 cycles,with a capacity decay of only 0.041％per cycle.This study has positive guiding significance for the design and development of high-performance lithium sulfur batteries.
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