Li–S batteries have attracted enormous interest due to their potentially high energy density, non-toxicity and the low cost of sulfur. The main challenges of sulfur cathodes are the short cycling life and limited power density caused by the low conductivity of sulfur and dissolution of Li polysulfides. Here we design a new double-hierarchical sulfur host to address these problems. Hierarchical carbon spheres (HCSs), constructed from building blocks of hollow carbon nanobubbles for loading sulfur, are sealed within a thin, polar MoS2 coating composed of ultrathin nanosheets. Experimental and theoretical studies show a strong absorption of the MoS2 nanoshell to polysulfides, and the excellent stability of the MoS2 nanosheets after the adsorption of polysulfides. Moreover, MoS2 promotes the electrochemical redox kinetics in Li–S batteries. Benefiting from the unique hierarchical, hollow and compositional characteristics of the host, the S/MoS2@HCS composite electrode shows a high capacity of 1048 mA h g–1 at 0.2C, good rate capacity and long cycling life with a slow capacity decay of 0.06% per cycle.
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机译：锂离子电池由于其潜在的高能量密度，无毒和低硫成本而引起了极大的兴趣。硫阴极的主要挑战是循环寿命短和功率密度受限，这是由于硫的电导率低和多硫化锂溶解造成的。在这里，我们设计了一个新的双层次硫磺宿主来解决这些问题。由中空碳纳米气泡的构建基块构成的用于装载硫的分层碳球（HCS）密封在由超薄纳米片组成的薄极性MoS2涂层中。实验和理论研究表明，MoS2纳米壳对多硫化物有很强的吸收性，并且在多硫化物吸附后，MoS2纳米片具有出色的稳定性。此外，MoS2促进Li-S电池的电化学氧化还原动力学。受益于宿主独特的分层，空心和组成特性，S / MoS2 @ HCS复合电极在0.2C的条件下显示出1048 mA hg –1 的高容量，良好的倍率容量和长循环寿命每周期0.06％的缓慢容量衰减。
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