Scalable AEM Electrolyzer Stack Operating with Tap Water

Clean hydrogen, that is hydrogen produced from water and renewable electricity by electrolysis without any CO2 emissions, is the most promising alternative to fossil fuels as an energy carrier and industrial feedstock. The U.S. Department of Energy's Hydrogen Shot Initiative aims to reduce the cost of 1 kg clean hydrogen to $1 by 2030, down from $5 today. This cost is currently adversely impacted by water electrolysis plants’ strict requirements for water purity, adding to the complexity of clean hydrogen production. We aim to establish tap water electrolysis as a viable method to produce clean hydrogen, eliminating the need for deionization of the process water. This will enable simpler plant design, smaller plant footprint, expanded locating possibilities, and ultimately lower the cost of clean hydrogen. However, the use of impure water is currently associated with increased degradation of the electrolyzer system. In this project, we will develop and test a range of promising electrolyzer components, component pretreatments, process conditions, and conditioning schedules to minimize the adverse e?ects of impure water. EvolOH’s anion exchange membrane electrolyzer is the perfect subject for this e?ort, as it is predicted to o?er the lowest hydrogen production costs of any water electrolyzer. In Phase I, we will focus on benchtop electrochemical and physical experiments to create shortlists of suitable components (e.g., catalysts, membranes) for impure water operation, based on prior internal and academic research. The components will be evaluated with and without additional pretreatments in synthetic tap water containing various impurity concentrations. We will also explore conditioning methods to periodically reverse water impurity-induced degradation on these components. At the end of Phase I, we will also test promising components in full electrolyzer cells operating with impure water to con?rm the validity of trends seen in the benchtop experiments. In Phase II, we will focus on device level experiments based on the promising materials, components, and conditioning treatments uncovered in Phase I. We will validate electrolyzer operation over >1,000 hours and implement the new components and process conditions in our large kW-scale electrolyzers. Further, we will adapt our in-house slot die manufacturing process to produce the tap water compatible electrodes with high quality. If successful, this project will make the deployment of water electrolyzers easier and cheaper, reducing clean hydrogen’s cost, increasing its market penetration – and thus contribute to a decarbonized future.