Large-current density and high-durability proton exchange membrane water electrolysis for practical hydrogen isotope separation

The separation of heavy hydrogen isotopes is very important for nuclear energy, medical, research and environmental safety. Water electrolysis with proton exchange membrane (PEM) electrolyzer is a promising way for hydrogen isotope separation due to its high efficiency, compact structure, and easy operation. Although some works have investigated the hydrogen isotope separation performance based on PEM electrolysis, few studies involve the high operation current density and long-term stability for practical use, and the influences of various critical operation factors on the separation performance are not systematically elucidated. In this study, a large-current density and high-durability PEM electrolyzer was constructed for hydrogen isotope separation. The influences of the deuterium content in feeding water, operation temperature, and current density on the hydrogen isotope separation performance including the separation factors in hydrogen gas and water at both anode and cathode sides during the PEM electrolysis were systematically investigated. Besides, a long-term deuterated water electrolysis at a high current density of 1 A/cm2 for more than 700 h shows a very stable isotope separation performance, demonstrating the practicability for large-scale hydrogen isotope separation. In addition, a calculation model proposed in this work elucidates the influences of the current density and temperature on the deuterium enrichment performance, which lays a solid foundation for the application of the PEM electrolysis in practical hydrogen isotope separation.