Theoretical studies on the ion migration through crystalline materials

离子在晶体材料中迁移的理论研究

• 批准号: 452995423
• 负责人: Professor Dr. Timo Jacob
• 金额: --
• 依托单位: Institut für Elektrochemie
• 依托单位国家: 德国
• 项目类别: Research Units
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/452995423?language=en
• 关键词: Theoretical; studies; ion; migration; through

Migration and diffusion of ions or atoms ontop or through solid materials is of interest not only for our fundamental understanding of mobility but also for various applications ranging from charge storage devices over fuel cells, membranes, polymers, sensors, and many more. While different experimental techniques have been developed to gain even atomically-resolved insights on such events, atomistic modelling is often restricted to rather limited and idealized model systems. However, to really capture the whole complexity of ion migration in realistic materials requires a multi-scale approach that is capable of describing concentration-dependent migration processes as well as structural diversities, e.g. defects or grain boundaries.Focusing on Li-borates as well as on perovskites as model systems that are available as well-defined crystalline materials (P1 Weitzel), the goal of this project is to study the relationship between structure (and composition) on the diffusion behaviour of cationic species and to resolve the complex potential energy landscape in these solid-state materials. Based on structural information on the bulk materials as well as well-defined grain boundaries (bicrystals) provided by the HR-TEM (P4 Jooss) and atom probe tomography (P3 Volkert) we will first study the morphology and electronic structure of the respective bulk systems using first principles methods (in particular DFT). The obtained information will then be used to optimize reactive forcefields for subsequent grand-canonical molecular dynamics (GC-MD) simulations on the system dynamics under varying conditions (e.g. temperature, ion loading, lattice defects, etc.). Here we will already be able to study both bulk systems as well as grain-boundaries in contact with an ion reservoir. These simulations will provide insights into the potential energy landscape of the material as well as the role of ionic and electronic charge mobility, information that can be compared to the experimental ToF-SIMS studies (P1 Weitzel) studies. In addition, the observed ion distribution within the material can be compared to the structural APT (P3 Volkert) and NMR (P2 Vogel) analyses, while the energetics will enter the mean-field simulations performed within P1 (Weitzel) and the Monte-Carlo studies of P5 (Maass). Finally, we will perform kinetic Monte-Carlo simulations in order to follow the CAIT experiment (P1 Weitzel) on larger time- and length-scales, where ion migration is induced by a concentration gradient. Again, the outcome will be readily comparable to the experiments performed in P1 (Weitzel) and the structural analyses of P3 (Volkert), P4 (Jooss) and P2 (Vogel).

离子或原子在固体材料上或通过固体材料的迁移和扩散不仅对于我们对迁移率的基本理解，而且对于从燃料电池、膜、聚合物、传感器等的电荷存储设备的各种应用都很感兴趣。虽然已经开发了不同的实验技术来获得对这些事件的原子解析的见解，但原子建模通常限于相当有限和理想化的模型系统。然而，为了真正捕获实际材料中离子迁移的整个复杂性，需要能够描述浓度依赖性迁移过程以及结构缺陷（例如缺陷或晶界）的多尺度方法。（P1 Weitzel），该项目的目标是研究结构（和组成）对阳离子物种扩散行为的关系，并解决这些固态材料中复杂的势能景观。基于HR-TEM（P4 Jooss）和原子探针层析成像（P3 Jooert）提供的大块材料以及明确的晶界（双晶）的结构信息，我们将首先使用第一原理方法（特别是DFT）研究相应大块系统的形态和电子结构。然后，所获得的信息将用于优化反应力场，用于在不同条件下（例如温度，离子负载，晶格缺陷等）对系统动力学进行后续的巨正则分子动力学（GC-MD）模拟。在这里，我们已经能够研究体系统以及与离子库接触的晶界。这些模拟将深入了解材料的势能景观以及离子和电子电荷迁移率的作用，这些信息可以与实验ToF-SIMS研究（P1 Weitzel）研究进行比较。此外，所观察到的材料内的离子分布可以与结构APT（P3 P3 ert）和NMR（P2 Vogel）分析进行比较，而能量学将进入P1（Weitzel）和P5（Maass）的蒙特-卡罗研究中进行的平均场模拟。最后，我们将进行动力学蒙特-卡罗模拟，以遵循CAIT实验（P1 Weitzel）在更大的时间和长度尺度上，其中离子迁移是由浓度梯度引起的。同样，结果将很容易与P1（Weitzel）中进行的实验以及P3（P3）、P4（Jooss）和P2（Vogel）的结构分析相比较。