Petrowsky Matt, Frech Roger
Department of Chemistry, University of Oklahoma, Norman, Oklahoma 73019, USA.
J Phys Chem B. 2009 Apr 30;113(17):5996-6000. doi: 10.1021/jp810095g.
The temperature-dependent conductivity originating in a thermally activated process is often described by a simple Arrhenius expression. However, this expression provides a poor description of the data for organic liquid electrolytes and amorphous polymer electrolytes. Here, we write the temperature dependence of the conductivity as an Arrhenius expression and show that the experimentally observed non-Arrhenius behavior is due to the temperature dependence of the dielectric constant contained in the exponential prefactor. Scaling the experimentally measured conductivities to conductivities at a chosen reference temperature leads to a "compensated" Arrhenius equation that provides an excellent description of temperature-dependent conductivities. A plot of the prefactors as a function of the solvent dielectric constant results in a single master curve for each family of solvents. These data suggest that ion transport in these and related systems is governed by a single activated process differing only in the activation energy for each family of solvents. Connection is made to the shift factor used to describe electrical and mechanical relaxation in a wide range of phenomena, suggesting that this scaling procedure might have broad applications.
源于热激活过程的温度依赖性电导率通常用简单的阿仑尼乌斯表达式来描述。然而，该表达式对有机液体电解质和非晶态聚合物电解质的数据描述欠佳。在此，我们将电导率的温度依赖性写成阿仑尼乌斯表达式，并表明实验观察到的非阿仑尼乌斯行为是由于指数前因子中包含的介电常数的温度依赖性所致。将实验测量的电导率按比例换算为选定参考温度下的电导率，会得到一个“补偿”的阿仑尼乌斯方程，它能很好地描述温度依赖性电导率。将前因子作为溶剂介电常数的函数作图，每个溶剂家族都会得到一条单一的主曲线。这些数据表明，这些体系及相关体系中的离子传输受单一激活过程支配，每个溶剂家族的激活能仅有所不同。文中还联系了用于描述广泛现象中电和机械弛豫的位移因子，这表明这种缩放程序可能有广泛的应用。
