Hydrogen storage for vehicles?

An American research team at the "Ford" automobile company in Dearborn, Michigan and the University of California, Los Angeles, have developed a new and original hydride that could be used as a useful starting point for the future development of hydrogen storage materials in the field of propulsion

Hydrogen is the fuel of humanity's future. Unfortunately for us, one problem remains: hydrogen is a gas and cannot be easily transferred into tanks, similar to liquid gasoline. Hydrogen storage in the form of solid hydrides, chemical compounds of hydrogen and metal (or semi-metal), are good storage materials in principle, but have not yet been properly adapted to propulsion applications.

An American research team at the "Ford" automobile company in Dearborn, Michigan and the University of California, Los Angeles, have now developed a new and original hydride that could be used as a useful starting point for the future development of hydrogen storage materials in the field of propulsion.

As reported by John Young and his team, an autocatalytic (self-catalyzed) reaction mechanism causes a compound containing three separate types of hydrides to release hydrogen quickly and at low temperatures and without any dangerous by-products. Certain hydrogen compounds, such as lithium borohydride (LiBH4) and magnesium hydride (MgH2), can release hydrogen and then also reabsorb it. However, their application in the field of propulsion contains several disadvantages: too high temperatures are required to release hydrogen, the rate of release and reabsorption is too slow and there are discharge reactions that release unwanted by-products such as ammonia. In addition, these compounds can "recharge" (absorb hydrogen) only under very high conditions of pressure and temperature. The combination of two different hydrides (two-component hydride) did show an advantage in the past in various uses, and this is because in the combined composition hydrogen is released at lower temperatures than in each of the hydrides separately.

The researchers, led by Yang, went a step further and added three hydrogen-containing compounds: lithium amide (LiNH2), lithium borohydride and magnesium hydride in a ratio of 2:1:1 to obtain a tertiary hydride. This ratio has much better properties than other known two-component combinations. The reason for this improvement is a complex sequence of reactions between the various components. The first reactions begin as soon as the components are mixed together. Heating the combination triggers additional reactions that release the hydrogen. The mixture is autocatalytic, which means that one of the reactions leads to the creation of the products in the next step, which accelerates the entire sequence of reactions. The direct result is a relatively low hydrogen release temperature and the release starts already at 150 0C

In addition, the released hydrogen is very pure since no volatile discharge products such as ammonia are obtained. Another advantage is that recharging of the tertiary combination is possible under relatively mild conditions.

to the original news based on the scientific article

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*Journal reference: "A Self-Catalyzing Hydrogen Storage", Materia lAngewandte. Chemie International Edition 2008, 47, DOI: 10.1002/anie.200703756.