论文标题
关于时间依赖的电解质塞贝克效应
On the time-dependent electrolyte Seebeck effect
论文作者
论文摘要
单离子Soret系数$α_{i} $表征了电解质溶液中离子以热梯度移动的趋势。当阳离子和阴离子之间的这些系数不同时，可以产生电场。为了使这种所谓的电解质塞贝克效应发生，例如，需要通过边界（例如电极）阻止不同的热填充通量。然后，电极的debye长度附近破坏了局部电荷中立性。令人困惑的是，许多作者将这些区域指向热电场的来源，但在时间依赖性的Seebeck系数$ s（t）$的推导中忽略了它们，给人一种错误的印象，即电解质塞贝克效果纯粹是纯粹的现象。在没有强制局部电负性的情况下，我们得出了由具有时间依赖于时间依赖的热梯度的二元电解质产生的$ s（t）$。接下来，我们在实验上测量$ s（t）$，用于钛电极附近的五种酸，碱和盐。对于稳态，我们发现$ s \ of2〜 \ mathrm {mv〜k}^{ - 1} $对于许多电解质，大约一个比基于文献$α_{i} $的预测大的数量级。我们将$ s（t）$的表达式适合于实验数据，将$α_{i} $视为拟合参数，并且还找到了比较大的值。
Single-ion Soret coefficients $α_{i}$ characterize the tendency of ions in an electrolyte solution to move in a thermal gradient. When these coefficients differ between cations and anions, an electric field can be generated. For this so-called electrolyte Seebeck effect to occur, the different thermodiffusive fluxes need to be blocked by boundaries -- electrodes, for example. Local charge neutrality is then broken in the Debye-length vicinity of the electrodes. Confusingly, many authors point to these regions as the source of the thermoelectric field yet ignore them in derivations of the time-dependent Seebeck coefficient $S(t)$, giving a false impression that the electrolyte Seebeck effect is purely a bulk phenomenon. Without enforcing local electroneutrality, we derive $S(t)$ generated by a binary electrolyte with arbitrary ionic valencies subject to a time-dependent thermal gradient. Next, we experimentally measure $S(t)$ for five acids, bases, and salts near titanium electrodes. For the steady state we find $S\approx2~\mathrm{mV~K}^{-1}$ for many electrolytes, roughly one order of magnitude larger than predictions based on literature $α_{i}$. We fit our expression for $S(t)$ to the experimental data, treating the $α_{i}$ as fit parameters, and also find larger-than-literature values, accordingly.
