Recent advances in the bipolar membrane and its applications

Bipolar membranes (BPMs) with a unique “sandwich” structure are a particular class of ion-exchange membranes. Under reverse bias, the unique water dissociation (WD) feature and the local pH control extensively apply the BPMs in acid/base production, resource separation and recovery. The WD resistance can be effectively reduced via the introduction of catalyst at the interfacial layer (IL) of BPMs. However, due to the imperfections of the IL, most BPMs have unwanted behaviors, such as high WD voltage, severe membrane delamination, catalyst leakage and high limiting current density, which leads to the large-scale industrial application of BPMs being unachievable. Therefore, based on the latest research progresses of BPMs, beginning with the WD mechanism of BPMs, this paper reviewed the research progress in three aspects: the types of interfacial layer catalyst, the construction methods of IL and the composite process of the membrane layers. Also, this paper deeply analyzed the merits and demerits of interfacial catalyst fixation methods such as immersion method, coating method, electrostatic assembly, in-situ growth and layer stacking, striving to provide corresponding theoretical support for the large-scale preparation of BPMs. Moreover, this paper also pointed out the bottleneck problem of BPMs and the crucial role of asymmetric BPM electrodialysis in industrial acid and base production. Finally, it was expected to explore the electrochemical application of BPMs, that was, efforts should be made to explore the application of BPMs in energy fields such as hydrogen generation by water electrolysis, carbon dioxide reduction, electrochemical synthesis of ammonia, fuel cells and liquid flow batteries, etc, so as to facilitate the evolution of BPMs. © 2024 Chemical Industry Press Co., Ltd.. All rights reserved.