Densified HKUST‑1 Monoliths as a Route to High Volumetric and Gravimetric Hydrogen Storage Capacity

We are currently witnessing the dawn of hydrogen (H2) economy, where H2 will soon become a primary
fuel for
heating, transportation, and long-distance and long-term energy storage.
Among diverse possibilities, H2 can be stored as a pressurized
gas, a cryogenic liquid, or a solid fuel via adsorption
onto porous materials. Metal–organic frameworks (MOFs) have
emerged as adsorbent materials with the highest theoretical H2 storage densities on both a volumetric and gravimetric basis.
However, a critical bottleneck for the use of H2 as a transportation
fuel has been the lack of densification methods capable of shaping
MOFs into practical formulations while maintaining their adsorptive
performance. Here, we report a high-throughput screening and deep
analysis of a database of MOFs to find optimal materials, followed
by the synthesis, characterization, and performance evaluation of
an optimal monolithic MOF (monoMOF) for H2 storage.
After densification, this monoMOF stores 46 g L–1 H2 at 50 bar and 77 K and delivers 41 and 42 g L–1 H2 at operating pressures of 25 and 50
bar, respectively, when deployed in a combined temperature–pressure
(25–50 bar/77 K → 5 bar/160 K) swing gas delivery system.
This performance represents up to an 80% reduction in the operating
pressure requirements for delivering H2 gas when compared
with benchmark materials and an 83% reduction compared to compressed
H2 gas. Our findings represent a substantial step forward
in the application of high-density materials for volumetric H2 storage applications.