Zhang Zexian, Zhou Shiyuan, Mei Tao, Gou Yanzhuo, Xie Fanxuan, Liu Chengcheng, Wang Xianbao
Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials, Ministry-of-Education Key Laboratory for the Green Preparation and Application of Functional Materials, Hubei Key Laboratory of Polymer Materials, School of Materials Science and Engineering, Hubei University, Wuhan 430062, PR China.
Dalton Trans. 2020 Jun 29;49(25):8591-8600. doi: 10.1039/d0dt01620a.
Capacity reduction mainly caused by the shuttle effect and low conductivity restricts the commercial application of lithium-sulfur batteries (LSBs). Herein, we developed a method to overcome these two obstacles synchronously by designing nitrogenous carbon decorated hollow Co3-xMnxO4/C nanocages as hosts of sulfur. These hosts were derived from manganese doped ZIF-67 by a facile sintering method, which provided polar surface to anchor lithium polysulfides and considerable electronic conductivity. The polar material Co3-xMnxO4 and special hollow frame contribute to efficient synergistic sulfur-fixation, resulting in great cycling stabilities. The manganese elements ensure an efficient conversion among LSPs. At the same time, N-doped carbon provides excellent electrical conductivity, thereby leading to splendid rate performances. Thus, a battery with great stability and high capacity could be achieved. As a result, Co3-xMnxO4/C/S with 66 wt% sulfur content delivered a high initial capacity of 1082 mA h g-1 at 1C, together with a slow average capacity decay of 0.056% per cycle at 10C over 500 cycles. When the average sulfur loading is 1.3 mg cm-2, a capacity of 628 mA h g-1 can be maintained at 5C after 500 cycles.
穿梭效应和低电导率导致的容量衰减限制了锂硫电池（LSBs）的商业应用。在此，我们通过设计含氮碳修饰的中空Co3-xMnxO4/C纳米笼作为硫宿主，开发了一种同步克服这两个障碍的方法。这些宿主由锰掺杂的ZIF-67通过简便的烧结方法衍生而来，其提供了极性表面以锚定多硫化锂并具有可观的电子导电性。极性材料Co3-xMnxO4和特殊的中空框架有助于实现高效的协同固硫，从而带来出色的循环稳定性。锰元素确保了多硫化物之间的高效转化。同时，氮掺杂碳提供了优异的导电性，进而带来出色的倍率性能。因此，可以实现具有高稳定性和高容量的电池。结果，硫含量为66 wt%的Co3-xMnxO4/C/S在1C下具有1082 mA h g-1的高初始容量，在10C下500次循环中平均容量衰减缓慢，每循环仅为0.056%。当平均硫负载为1.3 mg cm-2时，在5C下500次循环后仍可保持628 mA h g-1的容量。
