The performance of the gas diffusion electrode (GDE) is crucial for technical processes like chlorine–alkali electrolysis. The function of the GDE is to provide an intimate contact between gaseous reactants, the solid catalyst, and the liquid electrolyte. To accomplish this, the GDE is composed of wetting and non-wetting materials to avoid electrolyte breakthrough. Knowledge of the spatial distribution of the electrolyte in the porous structure is a prerequisite for further improvement of GDE. Therefore, the ability of the electrolyte to imbibe into the porous electrode is studied by direct numeric simulations in a reconstructed porous electrode. The information on the geometry, including the information on silver and PTFE distribution of the technical GDE, is extracted from FIB/SEM imaging including a segmentation into the different phases. Modeling of wetting phenomena inside the GDE is challenging, since surface tension and wetting of the electrolyte on silver and PTFE surfaces must be included in a physically consistent manner. Recently, wetting was modeled from first principles on the continuum scale by introducing a contact line force. Here, the newly developed contact line force model is employed to simulate two-phase flow in the solid microstructures using the smoothed particle hydrodynamics (SPH) method. In this contribution, we present the complete workflow from imaging of the GDE to dynamic SPH simulations of the electrolyte intrusion process. The simulations are used to investigate the influence of addition of non-wetting PTFE as well as the application of external pressure differences between the electrolyte and the gas phase on the intrusion process.

中文翻译：

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技术气体扩散电极中电解质分布的预测：从成像到 SPH 模拟

气体扩散电极 (GDE) 的性能对于氯碱电解等技术过程至关重要。GDE 的功能是提供气态反应物、固体催化剂和液体电解质之间的密切接触。为了实现这一点，GDE 由润湿和非润湿材料组成，以避免电解液渗漏。了解电解质在多孔结构中的空间分布是进一步改进 GDE 的先决条件。因此，通过在重建的多孔电极中的直接数值模拟来研究电解质吸收到多孔电极中的能力。几何信息，包括技术 GDE 的银和 PTFE 分布信息，是从 FIB/SEM 成像中提取的，包括对不同阶段的分割。GDE 内部润湿现象的建模具有挑战性，因为必须以物理一致的方式包括银和 PTFE 表面上电解质的表面张力和润湿。最近，通过引入接触线力，根据连续尺度的第一原理对润湿进行建模。在这里，新开发的接触线力模型用于使用平滑粒子流体动力学 (SPH) 方法模拟固体微观结构中的两相流动。在这篇文章中，我们展示了从 GDE 成像到电解质侵入过程的动态 SPH 模拟的完整工作流程。模拟用于研究添加非润湿 PTFE 以及电解质和气相之间的外部压力差对侵入过程的影响。