Lithium–sulfur batteries have been considered as one of the most promising energy storage devices due to their high theoretical capacity and low cost. They go through complicated multistep electrochemical reactions from solid (sulfur)–liquid (soluble polysulfide) to liquid (soluble polysulfide)–solid (Li₂S) during the discharge process. Actually, during this process, the transition from liquid phase (Li₂S₄) to solid phase (Li₂S) at 2.1 V plateau is a difficult step with sluggish kinetics, thus leading to low sulfur utilization and discharge capacity. To promote the transition processes and enhance the sulfur utilization, CoS₂@multichannel carbon nanofiber composites (CoS₂@MCNFs) serving as sulfur host were successfully synthesized. Herein, CoS₂ catalysts are proven to be beneficial not only for enhancing the phase-transition kinetics but also for adsorbing soluble polysulfide. Besides, unlike other carbon materials, MCNFs have plenty of hollow channels and thus enhance sulfur loading and conductivity. Accordingly, the discharge capacity increases 32% more than that of electrode without CoS₂. And a very low capacity fade rate of 0.03% per cycle (over 450 cycles) is obtained at a 0.5C rate. This work has opened up new ideas for enhancing sulfur utilization for high sulfur-loading electrode.

中文翻译：

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嵌入CoS2纳米粒子的双功能多通道碳框架：促进高负载Li-S电池的相变。

锂硫电池由于其高理论容量和低成本而被认为是最有前途的储能设备之一。他们在放电过程中经历了从固体（硫）-液体（可溶性多硫化物）到液体（可溶性多硫化物）-固体（Li ₂ S）的复杂的多步电化学反应。实际上，在此过程中，以2.1 V的平稳期从液相（Li ₂ S ₄）转变为固相（Li ₂ S）是一个动力学缓慢的困难步骤，因此导致硫的利用率和放电容量低。为了促进过渡过程并提高硫的利用率，CoS ₂ @多通道碳纳米纤维复合材料（CoS ₂（MCNFs）作为硫的主体已成功合成。在本文中，事实证明，CoS ₂催化剂不仅有益于增强相变动力学，而且有利于吸附可溶性多硫化物。此外，与其他碳材料不同，MCNFs具有大量的中空通道，因此增强了硫的含量和电导率。因此，放电容量比没有CoS ₂的电极增加32％。在0.5C的速率下，每个周期（超过450个周期）的电容衰减率非常低，仅为0.03％。这项工作为提高高硫负荷电极的硫利用率开辟了新思路。