Temperature and concentration dependence of the ionic transport properties of poly(ethylene oxide) electrolytes
Temperature and concentration dependence of the ionic transport properties of poly(ethylene oxide) electrolytes
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DOI：
10.1016/j.ssi.2021.115751
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发表时间：
2021-09-13
影响因子：
3.2
通讯作者：
Balsara, Nitash P.
中科院分区：
文献类型：
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作者：
Hoffman, Zach J.;Shah, Deep B.;Balsara, Nitash P.
尽管电池根据其用途和充电状态在不同的温度下工作，但很少有工作来了解温度对电解质离子传输特性的影响。这些特性的温度依赖性对于预测电池性能如何随温度变化非常重要，同时还能获得对这些电解质中离子传输基础的基本了解。在这项研究中，我们首次研究了温度对模型聚合物电解质的离子电导率、盐扩散系数、迁移数和热力学因子的影响：溶解在聚环氧乙烷（PEO）中的双（三氟甲磺酰）亚胺锂（LiTFSI）盐。这些特性是在 70、90 和 110 摄氏度下测量的。正如预期的那样，我们看到电导率和扩散随着温度的升高而单调增加。此外，还获得了转移数和热力学因子对温度的单调依赖性。人们推测，由于离子传输速度加快，浓差极化随着温度升高而降低。我们使用浓溶液理论来预测锂-PEO/LiTFSI-锂对称电池中的浓差极化，从而量化温度对浓差极化的影响。
Even though batteries operate at different temperatures depending on their use and state of charge, little work has been done to understand the effects of temperature on the ionic transport properties of the electrolyte. The temperature dependence of these properties is important for predicting how the performance of the battery will change as a function of temperature, along with gaining fundamental insights into the underpinnings of ion transport in these electrolytes. In this study we provide the first investigation of the effect of temperature on ionic conductivity, salt diffusion coefficient, transference number, and the thermodynamic factor of a model polymer electrolyte: lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) salt dissolved in poly(ethylene oxide) (PEO). These properties were measured at 70, 90, and 110 degrees C. As expected, we see monotonic increases in conductivity and diffusion with increasing temperature. Additionally, monotonic dependencies on temperature were obtained for the transference number and the thermodynamic factor. One presumes that concentration polarization decreases with increasing temperature due to more rapid ion transport. We use concentrated solution theory to predict concentration polarization in lithium-PEO/LiTFSI-lithium symmetric cells and thereby quantify the effect of temperature on concentration polarization.