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.

重氢同位素的分离对于核能、医学、研究和环境安全非常重要。质子交换膜（PEM）电解槽电解水具有效率高、结构紧凑、操作简单等优点，是一种很有前途的氢同位素分离方法。尽管一些工作已经研究了基于 PEM 电解的氢同位素分离性能，但很少有研究涉及实际使用的高操作电流密度和长期稳定性，并且没有系统地阐明各种关键操作因素对分离性能的影响。在这项研究中，构建了一种用于氢同位素分离的大电流密度和高耐久性 PEM 电解槽。进料水中氘含量、操作温度的影响，系统地研究了 PEM 电解过程中氢同位素分离性能和电流密度对氢同位素分离性能的影响，包括阳极和阴极侧氢气和水中的分离因子。此外，在1 A / cm 的高电流密度下进行长期氘化水电解²超过700 h表现出非常稳定的同位素分离性能，证明了大规模氢同位素分离的实用性。此外，该工作提出的计算模型阐明了电流密度和温度对氘富集性能的影响，为PEM电解在实际氢同位素分离中的应用奠定了坚实的基础。