In situ diagnosis of vacuum-deposited nanoscale ionic liquid [emim][TFSA], Li salt [Li][TFSA] and their solution films through a combination of ellipsometry and impedance spectroscopy
In situ diagnosis of vacuum-deposited nanoscale ionic liquid [emim][TFSA], Li salt [Li][TFSA] and their solution films through a combination of ellipsometry and impedance spectroscopy
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DOI：
10.35848/1347-4065/aba6cd
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发表时间：
2020-08
影响因子：
1.5
通讯作者：
R. Takazawa;Kaho Toyabe;S. Maruyama;Y. Matsumoto
中科院分区：
文献类型：
--
作者：
R. Takazawa;Kaho Toyabe;S. Maruyama;Y. Matsumoto
通过椭偏仪和交流阻抗谱的原位组合分析，研究了真空沉积的离子液体[EMIM][TFSA]、锂盐[Li][TFSA]及其在固体衬底上的溶液膜。椭圆偏振测量首次成功地应用于[EMIM][TFSA]离子液体薄膜沉积过程中的厚度监测，同时发现空气暴露后[Li][TFSA]薄膜的厚度增加。[Li][TFSA]薄膜的增厚是由于它的潮解性质，空气暴露的[Li][TFSA]薄膜与空气暴露前的绝缘固体相反，成为离子导体。发现[EMIM][TFSA]-[Li][TFSA]两层膜形成了均匀的溶液膜，[Li][TFSA]的摩尔分数高达0.7，明显高于相应的整体溶解度极限。还将讨论[EMIM][TFSA]-[Li][TFSA]薄膜的离子电导率与温度的关系以及空气暴露的影响。
As-vacuum-deposited ionic liquid [emim][TFSA], Li salt [Li][TFSA] and their solution films on solid substrates were investigated through an in situ combination analysis of ellipsometry and impedance spectroscopy. The ellipsometry measurement was first successfully applied to monitor the thickness of thin film [emim][TFSA] ionic liquid during the deposition, while it was revealed that the thickness of thin film [Li][TFSA] increased after air exposure. The thickness increase of the [Li][TFSA] film is due to its deliquescent property and the air-exposed [Li][TFSA] film became ion conducting in contrast to its insulating solid state before the air exposure. The two-layered [emim][TFSA]-[Li][TFSA] films were found to form homogeneous solution films with the mole fractions of [Li][TFSA] up to 0.7, significantly higher than the corresponding bulk solubility limit. The temperature dependence of, as well as the air exposure effect on, the ionic conductivity of [emim][TFSA]-[Li][TFSA] films will also be discussed.