Evidence of the hydrogen release mechanism in bulk MgH2

Kazuhiro Nogita, Xuan Q. Tran, Tomokazu Yamamoto, Eishi Tanaka, Stuart D. McDonald, Christopher M. Gourlay, Kazuhiro Yasuda, Syo Matsumura

Research output: Contribution to journalArticlepeer-review

40 Citations (Scopus)

Abstract

Hydrogen has the potential to power much of the modern world with only water as a by-product, but storing hydrogen safely and efficiently in solid form such as magnesium hydride remains a major obstacle. A significant challenge has been the difficulty of proving the hydriding/dehydriding mechanisms and, therefore, the mechanisms have long been the subject of debate. Here we use in situ ultra-high voltage transmission electron microscopy (TEM) to directly verify the mechanisms of the hydride decomposition of bulk MgH2 in Mg-Ni alloys. We find that the hydrogen release mechanism from bulk (2 μm) MgH2 particles is based on the growth of multiple pre-existing Mg crystallites within the MgH2 matrix, present due to the difficulty of fully transforming all Mg during a hydrogenation cycle whereas, in thin samples analogous to nano-powders, dehydriding occurs by a 'shrinking core' mechanism.

Original languageEnglish
Article number8450
JournalScientific reports
Volume5
DOIs
Publication statusPublished - Feb 13 2015

All Science Journal Classification (ASJC) codes

  • General

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