Balancing volumetric and gravimetric uptake in highly porous materials for clean energy

• Published in: Science (American Association for the Advancement of Science) Vol. 368; no. 6488; pp. 297 - 303
• Main Authors: Chen, Zhijie, Li, Penghao, Anderson, Ryther, Wang, Xingjie, Zhang, Xuan, Robison, Lee, Redfern, Louis R., Moribe, Shinya, Islamoglu, Timur, Gómez-Gualdrón, Diego A., Yildirim, Taner, Stoddart, J. Fraser, Farha, Omar K.
• Format: Journal Article
• Language: English
• Published: United States The American Association for the Advancement of Science 17.04.2020; AAAS
• Subjects: Alternative fuels; Aluminum; Clean energy; Computer simulation; Containers; Energy; Energy storage; Federal agencies; Fossil fuels; Gravimetry; Hydrogen; Hydrogen storage; Iron; Metal-organic frameworks; Methane; Nuclear fuels; Porosity; Porous materials; Pressure; Science & Technology - Other Topics; Scientific Concepts; Storage; Surface area; Work capacity; United States > US
• ISSN: 0036-8075; 1095-9203; 1095-9203
• DOI: 10.1126/science.aaz8881

The pressure for onboard storage of methane and hydrogen on vehicles is usually limited to 100 bar for the use of lightweight containers, but the amount stored can be increased with the use of absorbent materials. Efficient storage and delivery require a balance of volumetric and gravimetric storage. Chen et al. designed a metal-organic framework with trialuminum nodes and a large hexadentate aromatic linker that optimizes both parameters. This material surpassed the U.S. Department of Energy targets for methane and had a deliverable capacity of 14% by weight for hydrogen. Science , this issue p. 297 An aluminum-based framework material achieves high gravimetric and volumetric uptake and delivery of methane and hydrogen. A huge challenge facing scientists is the development of adsorbent materials that exhibit ultrahigh porosity but maintain balance between gravimetric and volumetric surface areas for the onboard storage of hydrogen and methane gas—alternatives to conventional fossil fuels. Here we report the simulation-motivated synthesis of ultraporous metal–organic frameworks (MOFs) based on metal trinuclear clusters, namely, NU-1501-M (M = Al or Fe). Relative to other ultraporous MOFs, NU-1501-Al exhibits concurrently a high gravimetric Brunauer−Emmett−Teller (BET) area of 7310 m 2 g −1 and a volumetric BET area of 2060 m 2 cm −3 while satisfying the four BET consistency criteria. The high porosity and surface area of this MOF yielded impressive gravimetric and volumetric storage performances for hydrogen and methane: NU-1501-Al surpasses the gravimetric methane storage U.S. Department of Energy target (0.5 g g −1 ) with an uptake of 0.66 g g −1 [262 cm 3 (standard temperature and pressure, STP) cm −3 ] at 100 bar/270 K and a 5- to 100-bar working capacity of 0.60 g g −1 [238 cm 3 (STP) cm −3 ] at 270 K; it also shows one of the best deliverable hydrogen capacities (14.0 weight %, 46.2 g liter −1 ) under a combined temperature and pressure swing (77 K/100 bar → 160 K/5 bar).