论文标题
离子液体溶剂邻近对电气双层的影响
Effect of proximity to ionic liquid-solvent demixing on electrical double layers
论文作者
论文摘要
对金属界面的离子液体（IL）和IL溶剂混合物的性质越来越感兴趣，尤其是由于它们在储能中的应用。迄今为止，主要的重点是远离相变的电气双层。然而，已知其相变附近的系统表现出一些显着的特征，例如润湿过渡和毛细管冷凝。本文中，我们开发了一种平均场模型，适用于接近固定的IL溶剂混合物，并将其与Carnahan-Starling（CS）和Lattice-Gas表达式结合使用，以进行排除的体积相互作用。然后，使用扰动扩展和数值对该模型进行分析求解。我们证明，除了众所周知的骆驼和钟形电容外，还有一个鸟类的电容，具有三个峰值作为电压的函数，这是由于靠近固定而出现的。此外，我们发现骆驼形电容是稀释电解质的标志，可以出现在高IL密度的离子电极。我们还讨论了在我们的模型背景下CS和晶格 - 气体表达式产生的差异和含义。
There is a growing interest in the properties of ionic liquids (ILs) and IL-solvent mixtures at metallic interfaces, particularly due to their applications in energy storage. The main focus so far has been on electrical double layers with ILs far from phase transitions. However, the systems in the vicinity of their phase transformations are known to exhibit some remarkable features, such as wetting transitions and capillary condensation. Herein, we develop a mean-field model suitable for the IL-solvent mixtures close to demixing, and combine it with the Carnahan-Starling (CS) and lattice-gas expressions for the excluded volume interactions. This model is then solved analytically, using perturbation expansion, and numerically. We demonstrate that, besides the well-known camel and bell-shaped capacitances, there is a bird-shaped capacitance, having three peaks as a function of voltage, which emerges due to the proximity to demixing. In addition, we find that the camel-shaped capacitance, which is a signature of dilute electrolytes, can appear at high IL densities for ionophobic electrodes. We also discuss the differences and implications arising from the CS and lattice-gas expressions in the context of our model.
