Nonlinear ion transport in the supercooled ionic liquid 1-hexyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide: Frequency dependence of third-order and fifth-order conductivity coefficients.
Nonlinear ion transport in the supercooled ionic liquid 1-hexyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide: Frequency dependence of third-order and fifth-order conductivity coefficients.
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过冷离子液体 1-己基-3-甲基咪唑鎓双（三氟甲基磺酰基）亚胺中的非线性离子输运：三阶和五阶电导率系数的频率依赖性。
DOI：
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发表时间：
2015
影响因子：
4.4
通讯作者：
B. Roling
中科院分区：
文献类型：
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作者：
L. N. Patro;O. Burghaus;B. Roling
我们对过冷离子液体1-己基-3-甲基咪唑双（三氟甲基磺酰基）亚胺[C6mim][NTf2]进行了非线性离子电导率的测量，施加了约200 kV/cm的交流电场。在这些场幅值下，检测了电流响应中的3ω和5ω谐波分量，并测定了高阶电导率系数σ3(1)、σ3(3)、σ5(3)和σ5(5)。详细分析了这些电导率系数与频率和温度的关系。主要发现如下：(1)三阶谱σ3(1)和σ3(3)在直流平台区表现出非常相似的值，但在色散区表现出很大的差异。五阶谱σ5(3)和σ5(5)也有相同的结果。（ii）在色散区，三阶谱最小，五阶谱最大。（iii）最小值和最大值的频率与低场直流电导率σ1，dc具有相同的活化能，而高阶电导率系数的dc值σ3，dc和σ5，dc具有较低的活化能。
We have carried out nonlinear ion conductivity measurements on the supercooled ionic liquid 1-hexyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide[C6mim][NTf2] by applying ac electric fields with amplitudes up to about 200 kV/cm. At these field amplitudes, 3ω and 5ω harmonic components in the current response were detected, and the higher-order conductivity coefficients σ3 (1),σ3 (3),σ5 (3), and σ5 (5) were determined. The frequency and temperature dependence of these conductivity coefficients was analyzed in detail. The most important findings were the following: (i) The third-order spectra σ3 (1) and σ3 (3) exhibit very similar values in the dc plateau regime but differ considerably in the dispersive regime. The same was observed for the fifth order spectra σ5 (3) and σ5 (5). (ii) In the dispersive regime, the third-order spectra display a minimum, while the fifth-order spectra display a maximum. (iii) The frequencies of these minima and maxima are thermally activated with the same activation energy as the low-field dc conductivity σ1,dc, whereas the dc values of the higher-order conductivity coefficients, σ3,dc and σ5,dc, are characterized by lower activation energies.