To be able to make hydrogen get in a regularly-sized fuel tank, car manufacturers rely on scientists for finding the best method to do that. Pressurized hydrogen tanks not only they do not provide enough pressure for the contained hydrogen to have an energy comparable to fossil fuels, but they are also hazardous and ultra-expensive. That’s why the scientific community looks at the option of solidifying the hydrogen, or attaching it to something solid, chemically.
Making hydrogen go solid would require about -259 degrees Celsius. To use it, you would have to transform it into a liquid by chilling it to -250 ºC. Even so, it would still not have enough energy density to take you 800 km with a tank.
Vitalij Pecharsky, a researcher from the U.S. DOE – Ames Laboratory, along with his team, studies the possibility of storing hydrogen at room temperatures, in a recyclable container – just like your car’s reservoir.
The team had used metals that could trap hydrogen in their structure, like alanaets, borohydrides, amides and imides, but these all proved they can only store a maximum of 10 percent hydrogen by weight.
A specially constructed ball mill allows Ames Laboratory researchers looking into solid hydrogen storage to mechanically combine materials under a high-pressure hydrogen environment to boost the amount of hydrogen the materials can store. The technique, called mechanochemical processing, could pave the way for hydrogen-fueled cars.
The fine powder mixture is next placed in a hardened steel vial along with steel balls. The vial is vigorously shaken. This acts to transfer energy into the materials. In addition, the rigorous mixing actually alters the materials’ crystallinity, provides mass transfer, and eventually – it is hoped – combines the materials and hydrogen gas into new fuel-ready compounds.
The Ames Lab group plans to mill various combinations of hydrides until they uncover the one that works best as a fuel. At some point in the future, this novel material could well become the fuel source for a hydrogen-powered car. The final product might be a powder or even a solid, removable block. Once in the tank, i’ll be warmed or agitated slightly. This will allow the hydrogen atoms to be released in the form of a gas. The gas in turn might then be converted into electricity via a fuel cell or simply burned by the engine.
The team plans to further enhancing the storing properties of the metal by using a combination of hydrides, reduced to nano-sized particles, making it easier to add a lot of extra hydrogen atoms, and recharged using the same milling process.
