The Soret effect in dry polymer electrolyte
The Soret effect in dry polymer electrolyte
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DOI：
10.1039/c9me00145j
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发表时间：
2020-05-01
影响因子：
3.6
通讯作者：
Hallinan, Daniel T., Jr.
中科院分区：
文献类型：
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作者：
Mentor, Jesufane Jenny;Torres, Richard;Hallinan, Daniel T., Jr.
当混合物暴露于温度梯度时，Soret效应导致浓度梯度。它是由温度梯度驱动的质量扩散（热扩散）和用于去除浓度梯度的质量扩散之间的平衡。因此，Soret效应在稳态下测量。在这项工作中，Soret效应进行了研究，在热原电池与锂金属电极和干聚合物电解质组成的聚（环氧乙烷）和锂双三氟甲磺酰亚胺（LiTFSI）。通过测量热原电池的电压来确定浓度梯度。这是在几个不同的温度梯度和四个不同的盐浓度进行检查。Soret系数被认为是类似于在小分子混合物和电解质中观察到的，并显着低于聚合物系统。对这一出乎意料的结果进行了解释。Soret系数被认为是浓度依赖性的，这需要进一步的调查。最后，证明了用于测量Soret系数的热原电池也可以用于发电。因此，聚合物电解质对于废热回收具有潜在的意义，并且热扩散可用于提高电池效率。
The Soret effect results in a concentration gradient when a mixture is exposed to a temperature gradient. It is a balance between diffusion of mass driven by the temperature gradient (thermal diffusion) and mass diffusion acting to remove the concentration gradient. Thus, the Soret effect is measured at steady state. In this work, the Soret effect was studied in a thermogalvanic cell with lithium metal electrodes and a dry polymer electrolyte composed of poly(ethylene oxide) and lithium bis-trifluoromethanesulfonylimide (LiTFSI). The concentration gradient was determined by measuring the voltage of the thermogalvanic cell. This was examined at several different temperature gradients and with four different salt concentrations. The Soret coefficient was found to be similar to that observed in small-molecule mixtures and electrolytes and significantly less than polymeric systems. An explanation for this unexpected result is proffered. The Soret coefficient was found to be concentration dependent, which requires further investigation. Finally, it was demonstrated that the thermogalvanic cells used to measure the Soret coefficient can also be used to generate power. Thus, polymer electrolytes are potentially of interest for waste heat recovery, and thermal diffusion might be used to improve battery efficiency.