Researchers have discovered an efficient method of hydrogen storage by developing a material with high storage capacity, deliverability, and structural robustness.
The storage of hydrogen is key to its applications. Developing adsorbent materials with high volumetric and gravimetric storage capacities, both essential for the efficient use of hydrogen as a fuel, is challenging, researchers said. Due to the low volumetric density of hydrogen, it requires 700-bar compressed tanks for storage and transport, making it a costly exercise with associated safety concerns.
The research on hydrogen storage has made progress in developing storage methods that meet gravimetric targets, which focus on the weight of the storage material. However, many of these materials have limited volumetric capacity, affecting the efficiency of space and subsequently impacting the driving range of fuel-cell vehicles.
In response to this problem, the researchers developed a controlled catenation strategy in hydrogen-bonded organic frameworks which aims to achieve a higher volumetric capacity, while balancing a high gravimetric capacity as well.
Researchers said the potential for hydrogen storage in molecular crystals has not been deeply explored because it is challenging to achieve large surface areas and high stabilities at the same time. The stability of the material is then, enhanced through catenation.
Catenation generally reduces surface areas and can result in non-porous materials by obstructing surface areas and so it has been avoided. Researchers in this study hypothesised, however, that catenation could be controlled precisely to avoid the loss of accessible surface areas, creating a robust material.
This design principle uses hydrogen bonding interactions instead of stacking to direct and define catenation. The catenated organic framework was then subjected to high and low pressures and it was found to successfully absorb and release hydrogen under both of these conditions.
This research demonstrates the potential of supramolecular crystals as promising candidates for onboard hydrogen storage and highlights the potential of a directional catenation strategy in designing robust porous materials with balanced high volumetric and gravimetric surface areas for applications, researchers concluded.
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