Due to its high theoretical capacity, high energy density, and easy availability, the lithium–sulfur (Li–S) system is considered to be the most promising candidate for electric and hybrid electric vehicle applications. Sulfur/carbon cathode in Li–S batteries still suffers, however, from low Coulombic efficiency and poor cycle life when sulfur loading and the ratio of sulfur to carbon are high. Here, we address these challenges by fabricating a sulfur/carboxylated–graphene composite using a reverse (water-in-oil) microemulsion technique. The fabricated sulfur–graphene composite cathode, which contains only 6 wt % graphene, can dramatically improve the cycling stability as well as provide high capacity. The electrochemical performance of the sulfur–graphene composite is further enhanced after loading into a three-dimensional heteroatom-doped (boron and nitrogen) carbon-cloth current collector. Even at high sulfur loading (∼8 mg/cm²) on carbon cloth, this composite showed 1256 mAh/g discharge capacity with more than 99% capacity retention after 200 cycles.

中文翻译：

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锂/硫电池硫/石墨烯复合材料的反向微乳液合成

由于其高理论容量，高能量密度和易用性，锂硫（Li–S）系统被认为是电动和混合动力电动汽车应用中最有希望的候选者。然而，当硫负载量和硫碳比高时，Li-S电池中的硫/碳阴极仍然受到库仑效率低和循环寿命差的困扰。在这里，我们通过使用反向（油包水）微乳液技术制造硫/羧化石墨烯复合材料来应对这些挑战。所制成的硫-石墨烯复合阴极仅包含6 wt％的石墨烯，可以显着提高循环稳定性并提供高容量。将硫-石墨烯复合材料装入三维杂原子掺杂的（硼和氮）碳布集电器后，其电化学性能得到进一步增强。即使在高硫负荷下（〜8 mg / cm²）在碳布上，该复合材料显示200次循环后的放电容量为1256 mAh / g，且保留率超过99％。