A Dual-Functioning Solid-Electrolyte Electrolyzer For Carbon-Negative Hydrogen Production

There are two major challenges that prevent conventional water electrolysis technology from meeting the Department of Energyĺs Hydrogen Shot goal of cutting the cost of clean hydrogen by 80% to only one dollar per one kilogram in one decade: i) the incremental technology advancements in traditional water electrolyzers and ii) the poor adaptability of traditional water electrolysis systems for coupled utilization of hydrogen with carbon. We propose to solve these two challenges by developing a novel water electrolyzer system that enables both efficient hydrogen generation and carbon capture. By supplying both hydrogen and carbon molecules as outputs, this dual-functioning water electrolyzer could function as an emission-free replacement for steam methane reforming. By electrochemically splitting carbonate/bicarbonate solutions, which contain carbon from a direct air capture or point source capture system, in a three-chamber porous solid electrolyte reactor, our water electrolyzer produces high-purity hydrogen and carbon dioxide gas streams from separate chambers. The two product streams from a single electrolyzer system considerably reduces the total cost allocation toward hydrogen manufacturing and improves the systemĺs adaptability for hydrogen utilization. By combining water electrolysis with carbon capture into one single electrolyzer design, we effectively cut the capital cost for hydrogen manufacturing in half. The extra cell voltage needed for water splitting in our reactor is also considerably lower than traditional electrolyzers. This presents a unique opportunity to meet the Department of Energyĺs Hydrogen Shot targets. The goal of the Phase I project is to demonstrate our novel water electrolyzer and validate the electrochemical performance through rigorous experimental design and performance testing while achieving operational stability (1000 hours with less than 10% voltage decay). By the end of Phase I, we will build a 500 square-centimeter prototype to deliver a production capacity of 25 kilograms of hydrogen while abating 1 tonne of carbon dioxide annually. We will then demonstrate the economic advantages of our design by constructing a comprehensive techno-economic analysis based on electrochemical performance from the prototype. If our technology were to progress to Phase II and Phase III and to be deployed at scale, it could reverse decades of emissions while also powering a clean energy future with hydrogen that has ultra-low carbon intensity. Assuming our reactor supplied 100% of global hydrogen demand today, we estimate it would remove 2.1-4.2 gigatonnes of atmospheric carbon dioxide per year (via direct air capture) while abating an additional 1.2 gigatonnes of carbon emissions per year (via displacing steam methane reforming). Our electrolyzer design could shift the paradigm for green hydrogen production to inherently include carbon capture, either for utilization or permanent sequestration.