Hydrogen production with seawater-resilient bipolar membrane electrolyzers

Marin, Daniela H, Perryman, Joseph T, Hubert, McKenzie A, Lindquist, Grace A, Chen, Lihaokun, Aleman, Ashton M, Kamat, Gaurav A, Niemann, Valerie A, Stevens, Michaela Burke, Regmi, Yagya ORCID: https://orcid.org/0000-0001-6588-7683, Boettcher, Shannon W, Nielander, Adam C and Jaramillo, Thomas F (2023) Hydrogen production with seawater-resilient bipolar membrane electrolyzers. Joule, 7 (4). pp. 765-781. ISSN 2542-4351

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Abstract

Generation of H2 and O2 from untreated water sources represents a promising alternative to ultrapure water required in contemporary proton exchange membrane-based electrolysis. Bipolar membrane-based devices, often used in electrodialysis and CO2 electrolysis, facilitate impure water electrolysis via simultaneous mediation of ion transport and enforcement of advantageous microenvironments. Herein we report their application in direct seawater electrolysis; we show that upon introduction of ionic species such as Na+ and Cl-, bipolar membrane electrolyzers inhibit the oxidation of Cl- to corrosive OCl- at the anode from real seawater down to a Faradaic efficiency of 0.005% while proton exchange membrane electrolyzers under comparable operating conditions exhibit a 10% Faradaic efficiency to Cl- oxidation. The effective mitigation of Cl- oxidation by bipolar membrane electrolyzers underpins their ability to enable longer term seawater electrolysis than proton exchange membrane assemblies by a factor of 140, suggesting a path to durable seawater electrolysis.