In-situ investigation of the hydrogen release mechanism in bulk Mg2NiH4

Xuan Quy Tran, Stuart D. McDonald, Qinfen Gu, Tomokazu Yamamoto, Koji Shigematsu, Kohei Aso, Eishi Tanaka, Syo Matsumura, Kazuhiro Nogita

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21 Citations (Scopus)

Abstract

Hydrogen storage is an important aspect to enable the so-called hydrogen economy. Mg-Ni alloys are among the most promising candidates for solid-state hydrogen storage systems yet many questions remain unanswered regarding the hydriding/dehydriding mechanism of the alloys. Mg2NiH4 particularly has received much attention both for its potential as a hydrogen storage medium and also exhibits interesting properties relating to its different polymorphs. Here, the dehydriding mechanism in bulk Mg2NiH4 is investigated using in-situ ultra-high voltage transmission electron microscopy (TEM) combined with Synchrotron powder X-ray diffraction (XRPD) and differential scanning calorimetry (DSC). We find that the hydrogen release is based on a mechanism of nucleation and growth of Mg2NiHx (x∼0–0.3) solid solution grains and is greatly enhanced in the presence of crystal defects occurring as a result of the polymorphic phase transformation. Also importantly, with atomic resolution TEM imaging a high density of stacking faults is identified in the dehydrided Mg2NiHx (x∼0–0.3) lattices.

Original languageEnglish
Pages (from-to)130-138
Number of pages9
JournalJournal of Power Sources
Volume341
DOIs
Publication statusPublished - Feb 15 2017

All Science Journal Classification (ASJC) codes

  • Renewable Energy, Sustainability and the Environment
  • Energy Engineering and Power Technology
  • Physical and Theoretical Chemistry
  • Electrical and Electronic Engineering

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    Tran, X. Q., McDonald, S. D., Gu, Q., Yamamoto, T., Shigematsu, K., Aso, K., Tanaka, E., Matsumura, S., & Nogita, K. (2017). In-situ investigation of the hydrogen release mechanism in bulk Mg2NiH4. Journal of Power Sources, 341, 130-138. https://doi.org/10.1016/j.jpowsour.2016.11.105