Japanese team creates Al-based hydrogen storage for fuel cells
A joint research group with members from the Japan Atomic Energy Agency (Hyogo, Japan) and Tohoku University (Sendai, Japan) has announced that they have developed a simple-structured, aluminium-based interstitial alloy that holds the potential to be used as hydrogen storage for fuel cells. The compound, Al2CuHx, was synthesised by hydrogenating Al2Cu at an extreme pressure of 10 gigapascals (1.5 million pounds per square inch) and a temperature of 800°C.
Lightweight interstitial hydrides, compounds in which hydrogen atoms occupy the interstices (spaces) between metal atoms, have been proposed as a safe and efficient means for storing hydrogen for fuel cell vehicles. Hydrides using magnesium, sodium and boron have been manufactured, but so far, none have proven practical as a hydrogen repository. An aluminium-based alloy hydride offers a more viable candidate because it has the desired traits of light weight, no toxicity to plants and animals, and absence of volatile gas products except for hydrogen. Until now, however, only complex aluminium hydrides (unsuitable for use as a hydrogen storage system) have been created.
The researchers characterized the conditions of the hydrogenation reaction using in-situ synchrotron radiation X-ray diffraction measurement, while the crystal and electron structures of the compound formed were studied with powder X-ray diffraction measurement and first-principle calculations, respectively. Together, these examinations confirmed the first-ever formation of an interstitial hydride of an aluminium-based alloy.
"Although its synthesis requires very extreme conditions and its hydrogen content is low, our new compound showed that an aluminium-based alloy hydride is achievable," said Hiroyuki Saitoh, lead author of the paper.
"Based on what we've learned from this first step, we plan to synthesise similar materials at more moderate conditions, products that hopefully will prove to be very effective at storing hydrogen."
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