1、文献讲解,报告人：秦蒙 2017年4月30日,Introduction,Advantages:1. As a typical representative of the most promising electrochemical energy storage systems, lithium-sulfur (Li-S) batteries have attracted numerous efforts due to its high theoretical specific capacity(1675 mAh g1) and energy density (2600 Wh kg1) as w
2、ell as its low cost. Disadvantage:1.the intermediate products from cyclo-S8, dissolved polysulfides(Li2Sm,m4), transport between the cathode and the anode with unfavorable reactions during charging-discharging process, leading to the “shuttle” problem; 2. the typical insulation of the active materia
3、ls (cyclo-S8) and the final products (Li2S).In this work, an ultra-microporous carbon (UMC) with uniform 0.55 nm pores was designed and prepared by polyvinylidenefluoride (PVDF) pyrolysis according to our previous work 29,30 for accommodating small sulfur molecules (S24) for Li-S battery.,Experiment
4、al,Figures,Figures,Figures,Figures,Figures,Conclusion,The UMC was prepared via a facile pyrolysis process for Li-S battery with good cycling stability, The UMC possesses abundant ultra-micropores with a uniform size of 0.55 nm, which could accommodate the small S24 molecules due to the size confinem
5、ent. With the absence of the unfavorable dissolved polysulfides caused by the cyclo-S8, the shuttle phenomenon is fundamentally avoided and the consequent good cycling stability can be obtained. The S/UMC-2 composite electrode has a capacity of 852 mAh g1 and Coulombic efficiency approaching 100% after 150 cycles at 0.1 C as well as a long-term cycling at 1 C for 1000 cycles with only around 0.03% capacity loss per cycle. These results provide a strong support to regard the S/UMC composites as a promising candidate for Li-S batteries and related systems.,
