Bielefeld Anja, Weber Dominik A, Janek Jürgen
Physikalisch-Chemisches Institut, Justus-Liebig-Universität, 35392 Giessen, Germany.
Volkswagen AG, Group Innovation, 38436 Wolfsburg, Germany.
ACS Appl Mater Interfaces. 2020 Mar 18;12(11):12821-12833. doi: 10.1021/acsami.9b22788. Epub 2020 Mar 5.
In the pursuit for future mobility, solid-state batteries open a wide field of promising battery concepts with a variety of advantages, ranging from energy density to power capability. However, trade-offs need to be addressed, especially for large-scale, cost-effective processing, which implies the use of a polymeric binder in the composite electrodes. Here, we investigate three-dimensional microstructure models of the active material, solid electrolyte, and binder to link cathode design and binder content with electrode performance. Focusing on lithium-ion transport, we evaluate the effective ionic conductivity and tortuosity in a flux-based simulation. Therein, we address the influence of electrode composition and active material particle size as well as the process-controlled design parameters of the void space and binder content. Even though added in small amounts, the latter has a strong negative influence on the ion transport paths and the active surface area. The simulation of ion transport within four-phase composites is supplemented by an estimation of the limiting current densities, illustrating that application-driven cell design starts at the microstructure level.
在对未来移动性的追求中，固态电池开启了一个充满前景的电池概念的广阔领域，具有从能量密度到功率能力等多种优势。然而，需要权衡一些因素，特别是对于大规模、具有成本效益的加工而言，这意味着在复合电极中使用聚合物粘合剂。在此，我们研究活性材料、固体电解质和粘合剂的三维微观结构模型，以将阴极设计和粘合剂含量与电极性能联系起来。聚焦于锂离子传输，我们在基于通量的模拟中评估有效离子电导率和曲折度。在其中，我们探讨电极组成、活性材料粒径以及孔隙空间和粘合剂含量的工艺控制设计参数的影响。尽管粘合剂添加量很少，但它对离子传输路径和活性表面积有很强的负面影响。通过对极限电流密度的估计补充了四相复合材料内离子传输的模拟，这表明应用驱动的电池设计始于微观结构层面。
