A novel amphoteric membrane was designed by blending polyvinylpyrrolidone (PVP) with sulfonated poly(ether ether ketone) (SPEEK) to fabricate a vanadium redox flow battery. Acid–base pairs were formed by sulfonic acid and heterocyclic nitrogen, and the dense network structures were interwoven by the hydrogen bonds between the acid–base pairs. Vanadium ions were blocked by these network structures such that their penetration was weakened. Compared with Nafion115 and SPEEK membranes, the ion selectivity of SPEEK/PVP (S/P) hybrid membranes of various proportions was improved, of which the S/P-30% membrane performed best (106.1*104 S min cm−3). At the same time, these hybrid membranes showed far superior performances than the single-component membranes in a single-cell system. Most notably, the coulombic efficiency and energy efficiency achieved by the battery with a S/P-30% hybrid membrane were 97.5% and 84.5% at 60 mA cm−2, respectively, with notable stability after 50 cycles. The corresponding open-circuit voltage of the battery was maintained above 0.8 V for more than 73 h. This acid–base hybrid membrane has reached a high level of overall performance in binary non-fluorine proton exchange membranes in recent years.

中文翻译：

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用于钒氧化还原液流电池的高选择性磺化聚（醚醚酮）/聚乙烯吡咯烷酮混合膜

通过将聚乙烯吡咯烷酮 (PVP) 与磺化聚醚醚酮 (SPEEK) 混合，设计了一种新型的两性膜，以制造钒氧化还原液流电池。酸碱对由磺酸和杂环氮形成，酸碱对之间的氢键交织形成致密的网络结构。钒离子被这些网络结构阻挡，从而削弱了它们的渗透性。与Nafion115和SPEEK膜相比，各种比例的SPEEK/PVP（S/P）杂化膜的离子选择性都有所提高，其中S/P-30%膜表现最好（106.1*104 S min cm-3）。同时，这些混合膜在单细胞系统中表现出远优于单组分膜的性能。最为显着地，具有 S/P-30% 混合膜的电池在 60 mA cm-2 下实现的库仑效率和能量效率分别为 97.5% 和 84.5%，并且在 50 次循环后具有显着的稳定性。电池相应的开路电压保持在 0.8 V 以上超过 73 小时。近年来，这种酸碱混合膜在二元非氟质子交换膜中达到了高水平的综合性能。