Department of Materials Science and Engineering, Cornell University, Ithaca, New York 14853, USA.
Department of Materials Science and Engineering, University of Florida, Gainesville, Florida 32611, USA.
J Chem Phys. 2019 Dec 21;151(23):234101. doi: 10.1063/1.5132354.
The ab initio computational treatment of electrochemical systems requires an appropriate treatment of the solid/liquid interfaces. A fully quantum mechanical treatment of the interface is computationally demanding due to the large number of degrees of freedom involved. In this work, we develop a computationally efficient model where the electrode part of the interface is described at the density-functional theory (DFT) level, and the electrolyte part is represented through an implicit solvation model based on the Poisson-Boltzmann equation. We describe the implementation of the linearized Poisson-Boltzmann equation into the Vienna Ab initio Simulation Package, a widely used DFT code, followed by validation and benchmarking of the method. To demonstrate the utility of the implicit electrolyte model, we apply it to study the surface energy of Cu crystal facets in an aqueous electrolyte as a function of applied electric potential. We show that the applied potential enables the control of the shape of nanocrystals from an octahedral to a truncated octahedral morphology with increasing potential.
电化学系统的从头算计算处理需要对固/液界面进行适当的处理。由于涉及到大量的自由度，因此对界面进行全量子力学处理在计算上是具有挑战性的。在这项工作中，我们开发了一种计算效率高的模型，其中界面的电极部分在密度泛函理论（DFT）水平上进行描述，而电解质部分则通过基于泊松-玻尔兹曼方程的隐式溶剂化模型来表示。我们描述了将线性化泊松-玻尔兹曼方程实现到维也纳从头算模拟包（一个广泛使用的 DFT 代码）中，然后对该方法进行验证和基准测试。为了展示隐式电解质模型的实用性，我们将其应用于研究在水溶液电解质中 Cu 晶体表面能作为外加电场的函数。我们表明，外加电场能够控制纳米晶体的形状，从八面体到截角八面体形态，随着电势的增加而增加。
