A Honeycomb-like Co@N-C Composite for Ultrahigh Sulfur Loading Li-S Batteries
A Honeycomb-like Co@N-C Composite for Ultrahigh Sulfur Loading Li-S Batteries
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用于超高硫负载锂硫电池的蜂窝状Co@N-C复合材料
DOI：
10.1021/acsnano.7b06061
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发表时间：
2017-11-01
期刊：
影响因子：
17.1
通讯作者：
Dong, Quanfeng
中科院分区：
文献类型：
--
作者：
Li, Yijuan;Fang, Jingmin;Dong, Quanfeng
锂硫电池的理论容量为1675 mAh g(-1)，能量密度为2600 Wh kg(-1)，因此备受关注。然而，在锂硫电池的实际应用中，如何实现阴极中硫的高利用率和高负荷仍然是一个巨大的挑战。本文采用简单的牺牲模板法，设计了蜂窝结构的准二维Co@N-C复合材料作为多功能硫宿主。具有大表面积和蜂窝状结构的细胞薄片可以封装更多的硫，从而形成高硫含量（HSC）复合材料，通过堆叠这些HSC薄片，由于其高层堆积密度，可以实现高硫负载（HSL）电极。与我们之前的多功能Co-N-C复合材料相比，细胞Co@N-C复合材料在硫含量、硫负荷、循环稳定性和速率性能方面都有明显的提高。利用细胞形态，可以同时获得HSC为93.6 wt %的复合材料和HSL为7.5 mg cm（-2）的电极，该复合材料在10 C （3.6 mg cm(-2)）下具有优异的倍率性能和良好的循环稳定性。
Because of the high theoretical capacity of 1675 mAh g(-1) and high energy density of 2600 Wh kg(-1), respectively, lithium-sulfur batteries are attracting intense interest. However, it remains an enormous challenge to realize high utilizations and loadings of sulfur in cathodes for the practical applications of Li-S batteries. Herein, we design a quasi-2D Co@N-C composite with honeycomb architecture as a multifunctional sulfur host via a simple sacrificial templates method. The cellular flake with large surface area and honeycomb architecture can encapsulate much more sulfur, leading to high sulfur content (HSC) composites, and by stacking these HSC flakes, a high sulfur loading (HSL) electrode can be realized due to their high layer bulk density. Compared to our previous work in multifunctional Co-N-C composites, the cellular Co@N-C composite displays a distinct enhancement in the sulfur content, sulfur loading, cycle stability, and rate performance. Benefiting from the cellular morphology, a composite with an HSC of 93.6 wt % and an electrode with an HSL of 7.5 mg cm(-2) can be obtained simultaneously, which exhibited excellent rate performance up to 10 C (3.6 mg cm(-2)) and great cycling stability.