Herrmann Elke, Dingenouts Nico, Roth Christina, Scheiba Frieder, Ehrenberg Helmut
Institute for Applied Materials (IAM), Karlsruhe Institute of Technology (KIT), 76344 Eggenstein-Leopoldshafen, Germany.
Institute for Chemical Technology and Polymer Chemistry (ITCP), Karlsruhe Institute of Technology (KIT), 76131 Karlsruhe, Germany.
Membranes (Basel). 2021 Jun 25;11(7):469. doi: 10.3390/membranes11070469.
Commercially available anion exchange membranes were retrieved from VRFB field tests and their degradation due to the various operation conditions is analyzed by in-situ and ex-situ measurements. Ion exchange capacity, permeability and swelling power are used as direct criteria for irreversible changes. Small-angle X-ray scattering (SAXS) and Differential scanning calorimetry (DSC) analyses are used as fingerprint methods and provide information about the morphology and change of the structural properties. A decrease in crystallinity can be detected due to membrane degradation, and, in addition, an indication of reduced polymer chain length is found. While the proton diffusion either increase or decline significantly, the ion exchange capacity and swelling power both are reduced. The observed extent of changes was in good agreement with in-situ measurements in a test cell, where the coulombic and voltage efficiencies are reduced compared to a pristine reference material due to the degradation process.
从全钒液流电池现场测试中获取市售阴离子交换膜，并通过原位和非原位测量分析其在各种运行条件下的降解情况。离子交换容量、渗透率和溶胀能力被用作不可逆变化的直接标准。小角X射线散射（SAXS）和差示扫描量热法（DSC）分析被用作指纹识别方法，提供有关形态和结构性能变化的信息。由于膜降解，可以检测到结晶度降低，此外，还发现了聚合物链长度缩短的迹象。虽然质子扩散显著增加或下降，但离子交换容量和溶胀能力均降低。观察到的变化程度与测试电池中的原位测量结果高度一致，在该测试电池中，由于降解过程，与原始参考材料相比，库仑效率和电压效率均降低。
