Poisoning Mechanism Map for Metal Hydride Hydrogen Storage Materials

The effective utilization of hydrogen storage materials (HSMs) is hindered by impurity gas poisoning, posing a significant challenge for large-scale applications. This study elucidates the poisoning mechanisms of various impurities gases (CO, CO₂, O₂, Ar, He, CH₄, N₂) on ZrCo, Pd, U and LaNi₅. Impurities gases are categorized into active and inactive types based on their effecting behaviors and mechanisms on the hydrogenation of HSMs. During the hydrogenation process, active impurities chemically poison the hydrogenation reaction by limiting hydrogen absorption at interface, while inactive impurities physically hinder hydrogenation reaction by impeding hydrogen diffusion in hydrogen-impurity mixed gas. In situ Scanning Tunneling Microscope clarifies these behaviors, and a novel criterion based on hydrogen spontaneous dissociation energy is introduced to explain and predict impurity-substrate interaction characteristics. The novel findings of this work provide a comprehensive framework for designing long-lived HSMs with poisoning resistance, guiding the development of more resilient hydrogen storage systems.