Supercell modeling of an electrical double layer (EDL) at electrified solid-electrolyte interfaces is a challenge. The net polarization of EDLs arising from the fixed chemical composition setup leads to uncompensated EDLs under periodic boundary condition and convolutes the calculation of the Helmholtz capacitance [C. Zhang and M. Sprik, Phys. Rev. B 94, 245309 (2016)]. Here we provide a new formula based on the supercell polarization at zero electric field Ē = 0 (i.e., standard Ewald boundary condition) to calculate the Helmholtz capacitance of charged insulator-electrolyte interfaces and validate it using atomistic simulations. Results are shown to be independent of the supercell size. This formula gives a shortcut to compute the Helmholtz capacitance without locating the zero net charge state of EDL and applies directly to any standard molecular dynamics code where the electrostatic interactions are treated by the Ewald summation or its variants.

中文翻译：

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通信：根据超级电池极化计算带电的绝缘体-电解质界面的亥姆霍兹电容

在带电的固体电解质界面上进行双电层（EDL）的超级电池建模是一项挑战。由固定的化学成分设置引起的EDL的净极化会导致在周期性边界条件下未补偿的EDL，并使Helmholtz电容的计算复杂化[C. Zhang和M. Sprik，物理学。版本B 94，245309（2016）]。在这里，我们提供了一个基于零电场下超级电池极化的新公式Ē= 0（即标准Ewald边界条件）以计算带电绝缘体-电解质界面的亥姆霍兹电容，并使用原子模拟对其进行验证。结果显示与超级电池大小无关。该公式为计算亥姆霍兹电容而无需定位EDL的零净电荷状态提供了捷径，并且可直接应用于通过Ewald求和或其变体处理静电相互作用的任何标准分子动力学代码。