Sulfur impregnated in a mesoporous covalent organic framework for high performance lithium–sulfur batteries
Sulfur impregnated in a mesoporous covalent organic framework for high performance lithium–sulfur batteries
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DOI：
10.1039/c5ra16235a
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发表时间：
2015-10
期刊：
影响因子：
3.9
通讯作者：
Xiaofei Yang;B. Dong;Hongzhang Zhang;R. Ge;Yanan Gao;Huamin Zhang
中科院分区：
文献类型：
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作者：
Xiaofei Yang;B. Dong;Hongzhang Zhang;R. Ge;Yanan Gao;Huamin Zhang
循环性能差一直被认为是阻碍锂硫(Li-S)电池实际应用的主要瓶颈，其主要原因是可溶性多硫化物在正负极之间穿梭(所谓的穿梭效应)。为了有效地解决这一问题，制备了一种孔分布规则的共价有机骨架(COF)偶氮-COF作为硫磺的主体。这种小的介孔不仅可以很好地将硫限制在纳米孔中，而且还可以为Li+提供一维(1D)的传输通道。得益于这一概念，即使没有LiNO_3添加剂，采用S/偶氮钴铁正极的Li-S电池组件在100次循环后仍表现出741 mA h g−1的高稳定容量，同时在0.1C下提供近1536 mA h g−1的高首次放电容量(1C=1672 mA g−1)。此外，当容量比(C-Rate)增加到2C时，20次循环后仍可获得770 mA h g−1的高容量，证明了良好的C-Rate性能。
Undesirable cycling performance has been considered as the main bottleneck that has hindered the practical application of lithium–sulfur (Li–S) batteries, which mainly results from soluble polysulfides shuttling between the anode and the cathode (so-called shuttle effect). To solve this problem effectively, a covalent organic framework (COF), Azo-COF, with a regular pore distribution of 2.6 nm was prepared as the host for sulfur. Such small mesopores can not only confine the sulfur well in the nanopores but also supply Li+ with one-dimension (1D) transmission channels. Benefiting from this concept, even without a LiNO3 additive, the Li–S battery assembly with a S/Azo-COF cathode presented a high stable capacity of 741 mA h g−1 after 100 cycles while delivering a high initial discharge capacity of nearly 1536 mA h g−1 at 0.1C (1C = 1672 mA g−1). Additionally, when the capacity rate (C-rate) was increased to 2C, a high discharge capacity of 770 mA h g−1 can be still achieved after 20 cycles, proving excellent C-rate performance.