Porous carbon felts (CFs) are widely used electrode materials for vanadium redox flow batteries (VRFBs). These materials differ in their precursor material, thickness, or graphitization degree and demonstrate broad differences in electrochemical performance. Prior to operation, an activation step, such as acid or heat treatment (HT), is commonly performed to improve their performance. A thermal treatment in air functionalizes the surface of the electrode and improves reaction kinetics as well as the wettability of the electrode. Herein, pristine and heat‐treated CFs are compared regarding their electrolyte wetting behavior for the use in VRFB. Contact angle (CA) measurements are conducted ex situ to investigate the effect of the HT. Furthermore, the porous CFs are examined in situ with an in‐house‐built flow cell regarding their invasion behavior with different types of electrolytes by X‐ray radiography. Additionally, the distribution of the electrolyte inside the felts is investigated by X‐ray tomography. The results demonstrate the effect of the HT and choice of electrolyte on the wetting behavior and electrolyte distribution.

中文翻译：

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X射线计算机射线照相和断层摄影术研究氧化还原液流电池的原始碳纤维和热处理碳纤维毡中电解质的侵入和分布

多孔碳毡（CF）是钒氧化还原液流电池（VRFB）广泛使用的电极材料。这些材料的前体材料，厚度或石墨化程度不同，并且电化学性能差异很大。在操作之前，通常执行活化步骤，例如酸或热处理（HT），以提高其性能。空气中的热处理可以使电极表面功能化，并改善反应动力学以及电极的润湿性。在此，对用于VRFB的原始CFs和热处理CFs的电解质润湿行为进行了比较。接触角（CA）测量是在非原位进行的，以研究HT的影响。此外，使用内部流动池对多孔CF进行了现场检查，以通过X射线照相对它们在不同类型的电解质中的侵入行为进行检查。此外，还可以通过X射线断层扫描技术研究毡内部电解质的分布情况。结果证明了高温和电解质的选择对润湿行为和电解质分布的影响。