Nanohydrogel Serving as Gas Transmitter Promotes the Efficient Storage of Hydrate-Based Solidified Hydrogen

Solid-state hydrogen storage by gas hydrates offers a novel pathway for large-scale, static, and mild storage. However, its application is hindered by inherently low storage and sluggish formation rate. In this work, nanohydrogels were synthesized and systematically evaluated for their performance, recyclability, and kinetic promotion effect on H 2 /DIOX binary hydrates. The results demonstrate that both particle size and concentration of nanohydrogels significantly influence their promoting performance. In particular, nanohydrogel N3 at a concentration of 0.3 wt % exhibited the best performance, achieving a hydrogen storage capacity of 0.517 wt %, representing a 127.7% increase compared to the pure 1,3-dioxolane (DIOX) system. The hydrate growth rate was also enhanced by 106.3%, marking a substantial improvement in efficiency over traditional systems. In addition, the promotion effect remained stable over 10 cycles, indicating excellent durability and reusability. Raman spectroscopy indicates that the hydrate formed is of structure II, and its crystal structure is not affected by the nanohydrogels. In situ μ-DSC disclosed the intricate effects of nanohydrogels on crystallization and demonstrated the condition-dependent nature of their promotion performance. Moreover, distinct from traditional approaches that focus on altering hydrate structures, this novel hydrogel promotes hydrate-based hydrogen storage by a dual mechanism of interfacial regulation and enhanced hydrogen transport, offering a new understanding and technological pathway for efficient hydrate-based hydrogen storage. This study not only overcomes the efficiency bottleneck in hydrogen storage by hydrate but also contributes significantly to its widespread commercial applications by robust stability and economic viability.