<p>Hydrogen energy is expected to contribute significantly to the reduction of CO₂ emissions. However, an effective large-scale supply system for hydrogen has not been established. In this study, hydrogenation of molten lithium was quantitatively investigated to develop a novel hydrogen-storage and transportation system using LiH as a storage medium. Consequently, the rate of H₂ absorption increased rapidly above the melting point of LiH and decreased with further increase in temperature. It was concluded that hydrogenation should be performed directly above the melting point of LiH. The rate of H₂ absorption increased with an increase in the surface area of the molten Li and decreased in deep Li pools. The material distribution during hydrogenation was investigated, and the downward and upward flows of molten LiH and molten Li, respectively, maintained the continuous absorption of H₂. The interfacial and surface properties affected the material distribution in the container. A large-scale process suitable for the efficient hydrogenation of Li was discussed, and a counter-flow-type was promising.</p> Graphical Abstract <p></p>