Abstract A hierarchically porous carbon nanofiber (HPCNF) material was prepared by a facile electrospinning method, with polyvinylpyrrolidone (PVP) as the carbon source and silica formed in-situ as the template. The carbon nanofibers showed a well-designed pore structure: centered macropores are surrounded by a denser cycle consisting of micro-/mesopores near the surface. Sulfur was encapsulated into the pores by solution penetration, followed by a melt diffusion method to generate a flexible sulfur/HPCNF (S/HPCNF) cloth as the binder-free cathode in lithium sulfur (Li-S) batteries. The HPCNF carbon with multi-scaled pores acts as an efficient host for large amounts of sulfur, and accommodates the associated volume expansion during electrochemical cycling. Moreover, the hierarchical architecture significantly reduces the escape of polysulfides during the cycling. The unique material allowed sulfur loading of 2.2–12.1 mg cm −2 , and exhibited a high sulfur utilization of more than 80% with high areal capacity of 11.3 mAh cm −2 , demonstrating that S/HPCNF is a promising cathode material for Li-S batteries of high energy density.

中文翻译：

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具有高硫负载量的根状多孔碳纳米纤维使锂硫电池具有优异的面积容量

摘要 以聚乙烯吡咯烷酮（PVP）为碳源，原位形成的二氧化硅为模板，采用简便的静电纺丝法制备了分级多孔碳纳米纤维（HPCNF）材料。碳纳米纤维显示出精心设计的孔结构：居中的大孔被更密集的循环包围，该循环由表面附近的微孔/中孔组成。通过溶液渗透将硫包封到孔中，然后通过熔体扩散方法生成柔性硫/HPCNF（S/HPCNF）布作为锂硫（Li-S）电池中的无粘合剂正极。具有多尺度孔隙的 HPCNF 碳作为大量硫的有效宿主，并在电化学循环过程中适应相关的体积膨胀。而且，分层结构显着减少了循环过程中多硫化物的逃逸。这种独特的材料允许硫负载为 2.2-12.1 mg cm -2 ，并表现出超过 80% 的高硫利用率和 11.3 mAh cm -2 的高面积容量，表明 S/HPCNF 是一种很有前途的锂离子正极材料。 S电池的高能量密度。