We conduct molecular dynamics simulations of electrical double-layer capacitors (EDLCs) using a library of ordered, porous carbon electrode materials called zeolite templated carbons (ZTCs). The well-defined pore shapes of the ZTCs enable us to determine the influence of pore geometry on both charging dynamics and charge storage mechanisms in EDLCs, also referred to as supercapacitors. We show that charging dynamics are negatively correlated with the pore-limiting diameter of the electrode material and display signatures of both progressive charging and ion trapping. However, the equilibrium capacitance, unlike charging dynamics, is not strongly correlated to commonly used, purely geometric descriptors such as pore size. Instead, we find a strong correlation of capacitance to the charge compensation per carbon (CCpC), a descriptor we define in this work as the average charge of the electrode atoms within the coordination shell of a counterion. A high CCpC indicates efficient charge storage, as the strong partial charges of the electrode are able to screen counterion charge, enabling higher ion loading and thus more charge storage within the electrode at a fixed applied voltage. We determine that adsorption sites with a high CCpC tend to be found within pockets with a smaller radius of curvature, where the counterions are able to minimize their distance with multiple points on the electrode surface, and therefore induce stronger local partial charges.

中文翻译：

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具有规则孔几何形状的碳产生了超级电容器电荷存储的基本原理

我们使用称为沸石模板碳（ZTC）的有序多孔碳电极材料库对双电层电容器（EDLC）进行分子动力学模拟。ZTC的明确定义的孔形状使我们能够确定孔几何形状对EDLC（也称为超级电容器）中的电荷动力学和电荷存储机制的影响。我们表明，充电动力学与电极材料的限孔直径呈负相关，并且显示出渐进充电和离子捕获的特征。但是，与充电动力学不同，平衡电容与常用的纯几何描述变量（例如孔径）之间的相关性不强。相反，我们发现电容与每碳电荷补偿（CCpC）有很强的相关性，我们在这项工作中定义的描述符是抗衡离子配位壳内电极原子的平均电荷。高CCpC表示有效的电荷存储，因为电极的强部分电荷能够屏蔽抗衡离子电荷，从而实现更高的离子负载量，从而在固定的施加电压下在电极内提供更多的电荷存储。我们确定具有较高CCpC的吸附位点倾向于在曲率半径较小的凹穴中找到，其中的抗衡离子能够在电极表面上的多个点使它们的距离最小化，并因此产生较强的局部偏电荷。因为电极的强部分电荷能够屏蔽抗衡离子电荷，因此能够实现更高的离子负载量，从而在固定的施加电压下在电极内存储更多的电荷。我们确定具有较高CCpC的吸附位点倾向于在曲率半径较小的凹穴中找到，其中的抗衡离子能够在电极表面上的多个点使它们的距离最小化，并因此产生较强的局部偏电荷。因为电极的强部分电荷能够屏蔽抗衡离子电荷，因此能够实现更高的离子负载量，从而在固定的施加电压下在电极内存储更多的电荷。我们确定具有较高CCpC的吸附位点倾向于在曲率半径较小的凹穴中找到，其中的抗衡离子能够在电极表面上的多个点使它们的距离最小化，并因此产生较强的局部偏电荷。