Kosov Alexander V, Grishenkova Olga V, Isaev Vladimir A, Zaikov Yuriy
Institute of High Temperature Electrochemistry, Ural Branch of the Russian Academy of Sciences, 620990 Yekaterinburg, Russia.
Materials (Basel). 2022 May 18;15(10):3603. doi: 10.3390/ma15103603.
The problem of diffusion-controlled growth following an instantaneous nucleation event was studied within the framework of a new numerical model, considering the spatial distribution of hemispherical nuclei on the electrode surface and the mutual influence of growing nuclei via the collision of 3D diffusion fields. The simulation of the diffusion-controlled growth of hexagonal and random ensembles was performed at the overpotential-dependent number density of nuclei. The diffusion flow to each nucleus within a random ensemble was simulated by the finite difference method using the derived analytical expressions for the surface areas and the volumes formed at the intersection of 3D diffusion fields with the side faces of a virtual right prism with a Voronoi polygon base. The implementation of this approach provides an accurate calculation of concentration profiles, time dependences of the size of nuclei, and current transients. The results, including total current density transients, growth exponents, and nucleus size distribution, were compared with models developed within the concept of planar diffusion zones, the mean-field approximation and the Brownian dynamics simulation method, as well as with experimental data from the literature. The prospects of the model for studying the initial stages of electrocrystallization were discussed.
在一个新的数值模型框架内，研究了瞬时成核事件后扩散控制生长的问题，该模型考虑了电极表面半球形核的空间分布以及通过三维扩散场碰撞而生长的核之间的相互影响。在与过电位相关的核数密度下，对六边形和随机集合的扩散控制生长进行了模拟。利用导出的解析表达式，通过有限差分法模拟了随机集合中每个核的扩散流，该表达式用于计算三维扩散场与具有Voronoi多边形底面的虚拟直棱柱侧面相交处形成的表面积和体积。这种方法的实施能够准确计算浓度分布、核尺寸的时间依赖性以及电流瞬变。将包括总电流密度瞬变、生长指数和核尺寸分布在内的结果与基于平面扩散区概念、平均场近似和布朗动力学模拟方法建立的模型以及文献中的实验数据进行了比较。讨论了该模型在研究电结晶初始阶段的前景。
