Wang Shunli, Liang Ying, Dai Tingting, Liu Yalin, Sui Zhuyin, Tian Xinlong, Chen Qi
State Key Laboratory of Marine Resource Utilization in South China Sea, Hainan Provincial Key Lab of Fine Chemistry, School of Chemical Engineering and Technology, Hainan University, Haikou 570228, China.
School of Chemistry & Chemical Engineering, Yantai University, Yantai 264005, China.
J Colloid Interface Sci. 2021 Jun;591:264-272. doi: 10.1016/j.jcis.2021.02.010. Epub 2021 Feb 6.
Covalent organic frameworks (COFs) with pre-designed structure and customized properties have been employed as sulfur storage materials for lithium-sulfur (Li-S) batteries. In this work, a cationic mesoporous COF (COF-NI) was synthesized by grafting a quaternary ammonium salt group onto the pore channel of COFs via a one-pot three components tandem reaction strategy. The post-functionalized COFs were utilized as the matrix framework to successfully construct the Li-S battery with high-speed capacity and long-term stability. The experimental results showed that, after loading active material sulfur, cationic COF-NI effectively suppressed the shuttle effect of the intermediate lithium polysulfide species in Li-S batteries, and exhibited better cycle stability than the as-obtained neutral COF (COF-Bu). For example, compared with COF-Bu based sulfur cathode (521 mA h g), the cationic COF-NI based sulfur cathode maintained a discharge capacity of 758 mA h g after 100 cycles. These results clearly showed that appropriate pore environment of COFs can be prepared by rational design, which can reduce the shuttle effect of lithium polysulfide species and improve the performance of Li-S battery.
具有预先设计结构和定制性质的共价有机框架（COFs）已被用作锂硫（Li-S）电池的硫储存材料。在这项工作中，通过一锅三组分串联反应策略将季铵盐基团接枝到COFs的孔道上，合成了一种阳离子介孔COF（COF-NI）。后功能化的COFs被用作基质框架，成功构建了具有高倍率容量和长期稳定性的Li-S电池。实验结果表明，在负载活性物质硫后，阳离子COF-NI有效抑制了Li-S电池中中间多硫化锂物种的穿梭效应，并且比所得的中性COF（COF-Bu）表现出更好的循环稳定性。例如，与基于COF-Bu的硫阴极（521 mA h g）相比，基于阳离子COF-NI的硫阴极在100次循环后保持758 mA h g的放电容量。这些结果清楚地表明，通过合理设计可以制备合适的COFs孔环境，这可以减少多硫化锂物种的穿梭效应并提高Li-S电池的性能。
