Image: University of Oregon
University of Oregon (UO) chemists have
developed a boron-nitrogen-based liquid-phase storage material for hydrogen
that works safely at room temperature and is both air- and moisture-stable—an
accomplishment that offers a possible route through current storage and
Reporting in a paper placed online ahead of publication
in the Journal of the American Chemical
Society, a team of four UO scientists describes the development of a cyclic
amine borane-based platform called BN-methylcyclopentane. In addition to its
temperature and stability properties, it also features hydrogen desorption,
without any phase change, that is clean, fast, and controllable. It uses
readily available iron chloride as a catalyst for desorption, and allows for
recycling of spent fuel into a charged state.
The big challenges to move this storage platform forward,
researchers cautioned, are the needs to increase hydrogen yield and develop a
more energy efficient regeneration mechanism.
“In addition to renewable hydrogen production, the
development of hydrogen storage technologies continues to be an important task
toward establishing a hydrogen-based energy infrastructure,” says Shih-Yuan
Liu, professor of chemistry and researcher in the UO Material Sciences
The U.S. Department of Energy, which funded the research,
is shooting to develop a viable liquid or solid carrier for hydrogen fuel by
2017. The new UO approach differs from many other technologies being studied in
that it is liquid-based rather than solid, which, Liu says, would ease the
possible transition from a gasoline to a hydrogen infrastructure.
“The field of materials-based hydrogen storage has
been dominated by the study of solid-phase materials such as metal hydrides,
sorbent materials, and ammonia borane,” Liu says. “The availability
of a liquid-phase hydrogen storage material could represent a practical
hydrogen storage option for mobile and carrier applications that takes
advantage of the currently prevalent liquid-based fuel infrastructure.”
The key is in the chemistry. Liu’s team originally
discovered six-membered cyclic amine borane materials that readily trimerize—form
a larger desired molecule—with the release of hydrogen. These initial
materials, however, were solids. By tweaking the structure, including reducing
the ring size from 6- to a 5-membered ring, the group succeeded in creating a
liquid version that has low vapor pressures and does not change its liquid property
upon hydrogen release.
Initially, Liu says, the new platform could be more
readily adopted for use in portable fuel cell-powered devices.