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arXiv 2005.02851physics.chem-phcond-mat.mes-hallcond-mat.mtrl-scicond-mat.softphysics.app-ph
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纳米多孔碳中的离子液体动力学:超级电容器材料的孔径和温度相关的中子能谱研究

Ionic liquid dynamics in nanoporous carbon: A pore-size- and temperature-dependent neutron spectroscopy study on supercapacitor materials

Mark Busch, Tommy Hofmann, Bernhard Frick, Jan P. Embs, Boris Dyatkin, Patrick Huber

摘要:

用准弹性中子谱研究了空间约束对室温离子液体1-N-丁基吡啶双(三氟甲基磺酰基)酰亚胺([BuPy][Tf_2N])在不同孔径的多孔碳中的热激发随机阳离子动力学的影响。使用固定窗口扫描的潜力,即扫描样本参数,同时仅观察一个特定的能量传递值,获得宽温度范围内的动态景观的概览。它表明,这些数据已经提供了一个相当全面的了解的约束引起的改变的分子流动性相比,散装。一个互补的,更详细的分析,在选定的温度下的全能量转移谱揭示了两个平移扩散过程在不同的时间尺度上。两者都比在本体液体中慢得多,并且随着纳米孔尺寸的减小,各自的自扩散系数降低。具有相似孔径的纳米多孔碳中分子自扩散的不同热活化能表明孔形态对分子流动性的重要性,超出了纯粹的限制程度。尽管动态减慢,我们可以表明,纳米约束后的液体状态的温度范围显着扩展到低得多的温度,这是有益的潜在的技术应用,这样的系统。

英文摘要:

The influence of spatial confinement on the thermally excited stochastic cation dynamics of the room-temperature ionic liquid 1-N-butylpyridinium bis-((trifluoromethyl)sulfonyl)imide ([BuPy][Tf_2N]) inside porous carbide-derived carbons with various pore sizes in the sub- to a few nanometer range are investigated by quasi-elastic neutron spectroscopy. Using the potential of fixed window scans, i.e. scanning a sample parameter, while observing solely one specific energy transfer value, an overview of the dynamic landscape within a wide temperature range is obtained. It is shown that already these data provide a quite comprehensive understanding of the confinement-induced alteration of the molecular mobility in comparison to the bulk. A complementary, more detailed analysis of full energy transfer spectra at selected temperatures reveals two translational diffusive processes on different time scales. Both are considerably slower than in the bulk liquid and show a decrease of the respective self-diffusion coefficients with decreasing nanopore size. Different thermal activation energies for molecular self-diffusion in nanoporous carbons with similar pore size indicate the importance of pore morphology on the molecular mobility, beyond the pure degree of confinement. In spite of the dynamic slowing down we can show that the temperature range of the liquid state upon nanoconfinement is remarkably extended to much lower temperatures, which is beneficial for potential technical applications of such systems.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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