Effect of Co-Substitution on Hydrogen Absorption and Desorption Reactions of YMgNi4-Based Alloys

Toyoto Sato, Kazutaka Ikeda, Takashi Honda, Luke L. Daemen, Yongqiang Cheng, Toshiya Otomo, Hajime Sagayama, Anibal J. Ramirez-Cuesta, Shigeyuki Takagi, Tatsuoki Kono, Heena Yang, Wen Luo, Loris Lombardo, Andreas Züttel, Shin Ichi Orimo

Research output: Contribution to journalArticlepeer-review

Abstract

YMgNi4-based alloys exhibit reversible hydrogen absorption and desorption reactions at near room temperature. Here, we report that Co-substituted YMgNi4-based alloys exhibited higher hydrogen contents and lower hydrogen absorption and desorption reaction pressures than unsubstituted alloys. The effects of Co-substitution viewed from atomic arrangements were particularly clarified by synchrotron radiation powder X-ray diffraction, neutron diffraction, and inelastic neutron scattering. Powder neutron diffraction of the Co-substituted alloy at 5 MPa of D2 pressure suggested the formation of -phase deuteride (higher deuterium content) from β-phase deuteride (lower deuterium content). However, no -phase deuteride was observed in the unsubstituted alloys at 5 MPa. Therefore, the -phase deuteride formation of the Co-substituted alloy at lower pressure led to higher hydrogen contents than the unsubstituted alloys. The combined results of powder neutron diffraction and inelastic neutron scattering suggested that the -phase hydride of the Co-substituted alloy was continuously generated due to additional H atoms at the H atom sites in the β-phase hydride because of the disordered H atomic arrangement involving H-H interactions. As a result, hydrogen absorption and desorption reaction pressures for the -phase deuteride formation with higher hydrogen storage capacity were lowered.

Original languageEnglish
JournalJournal of Physical Chemistry C
DOIs
Publication statusAccepted/In press - 2022

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Energy(all)
  • Physical and Theoretical Chemistry
  • Surfaces, Coatings and Films

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