Horike Shohei, Nandal Vikas, Wei Qingshuo, Seki Kazuhiko
Department of Chemical Science and Engineering, Graduate School of Engineering, Kobe University, 1-1 Rokkodai-cho, Kobe 657-8501, Japan.
Center for Membrane and Film Technology, Kobe University, 1-1 Rokkodai-cho, Kobe 657-8501, Japan.
ACS Appl Mater Interfaces. 2025 Jan 22;17(3):4984-4995. doi: 10.1021/acsami.4c19795. Epub 2025 Jan 10.
Recently, ionic thermoelectric supercapacitors have gained attention because of their high open circuit voltages, even for ions that are redox inactive. As a source of open circuit voltage (electromotive force), an asymmetry in electric double layers developed by the adsorption of ions at the electrode surfaces kept at different temperatures has previously been proposed. As another source, the Eastman entropy of transfer, which is related to the Soret coefficient, has been considered. Herein, we theoretically estimated the open circuit voltages generated in the Stern layer, the diffuse layer and by the Eastman entropy of transfer. The Grahame equation has been generalized to consider the temperature gradient in the diffuse layer. The ion coverage difference between the hot and cold electrodes and the open circuit voltage are obtained by solving self-consistent equations using the adsorption isotherm. The results are compared with experimental results using a metal electrode and a conductive polymer-based electrode. We show the possible origin of the high ionic Seebeck effect caused by the asymmetry in the coverages of adsorbed ions in terms of the various types of interface capacitance factor at the hot and cold electrodes.
最近，离子热电器件因其高开路电压而受到关注，即使对于那些无氧化还原活性的离子也是如此。作为开路电压（电动势）的来源，此前有人提出，在保持不同温度的电极表面，离子吸附所形成的双电层不对称性是其来源之一。作为另一个来源，与索雷特系数相关的伊斯特曼转移熵也被考虑在内。在此，我们从理论上估算了在斯特恩层、扩散层以及由伊斯特曼转移熵产生的开路电压。格雷厄姆方程已被推广，以考虑扩散层中的温度梯度。通过使用吸附等温线求解自洽方程，可得到热电极和冷电极之间的离子覆盖差异以及开路电压。将结果与使用金属电极和基于导电聚合物的电极的实验结果进行了比较。我们从热电极和冷电极处各种类型的界面电容因子的角度，展示了由吸附离子覆盖不对称性导致的高离子塞贝克效应的可能起源。
