Asymmetric Bipolar Membrane for High Current Density Electrodialysis Operation with Exceptional Stability

Journal Article · Fri Nov 08 00:00:00 EST 2024 · ACS Energy Letters

DOI:https://doi.org/10.1021/acsenergylett.4c01662· OSTI ID:2571633

Lucas, Éowyn; Bui, Justin C; Stovall, Timothy Nathan; Hwang, Monica; Wang, Kaiwen; Dunn, Emily R; Spickermann, Ellis; Shiau, Lily; Kusoglu, Ahmet; Weber, Adam Z; Bell, Alexis T; Ardo, Shane; Atwater, Harry A; Xiang, Chengxiang

Bipolar membranes (BPMs) enable isolated acidic/alkaline regions in electrochemical devices, facilitating optimized environments for electrochemical separations and catalysis. For economic viability, BPMs must attain stable, high current density operation with low overpotentials in a freestanding configuration. We report an asymmetric, graphene oxide (GrOx)-catalyzed BPM capable of freestanding electrodialysis operation at 1 A cm–2 with overpotentials <250 mV. Use of a thin anion-exchange layer improves water transport while maintaining near unity Faradaic efficiency for acid and base generation. Voltage stability exceeding 1100 h with an average drift of 70 μV/h at 80 mA cm–2 and 100 h with an average drift of −300 μV/h at 500 mA cm–2 and implementation in an electrodialysis stack demonstrate real-world applicability. Continuum modeling reveals that water dissociation in GrOx BPMs is both catalyzed and electric-field enhanced, where low pK a moieties on GrOx enhance local electric fields and high pK a moieties serve as active sites for surface-catalyzed water dissociation. These results establish commercially viable BPM electrodialysis and provide fundamental insight to advance design of next-generation devices.

• Research Organization: Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)
• Sponsoring Organization: US Department of Energy; USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22), Chemical Sciences, Geosciences & Biosciences Division (SC-22.1)
• Grant/Contract Number: AC02-05CH11231
• OSTI ID: 2571633
• Journal Information: ACS Energy Letters, Journal Name: ACS Energy Letters Journal Issue: 11 Vol. 9
• Country of Publication: United States
• Language: English