Microstructural evolution and hydrogen storage proprieties of melt-spun eutectic Mg76.87Ni12.78Y10.35 alloy with low hydrides formation/decomposition enthalpy

Wenjie Song, Jie Liu, Huiping Dong, Guang Zhang, Jianghua Shen, Youxing Chen, Qiuming Wei

Research output: Contribution to journalArticlepeer-review

19 Scopus citations

Abstract

Ternary eutectic Mg76.87Ni12.78Y10.35 (at. %) ribbons with mixed amorphous and nanocrystalline phases were prepared by melt spinning. The microstructures of the melt-spun, hydrogenated and dehydrogenated samples were examined and compared by X-ray diffraction and transmission electron microscopy. The amorphous structure transforms into a thermally stable nanocrystalline structure with a grain size of about 5 nm during hydrogen ab/desorption cycles. The Mg, Mg2Ni and phases with Y in the melt-spun state transform into MgH2, Mg2NiH4, Mg2NiH0.3, YH2 and YH3 after hydrogenation, and transform back to Mg, Mg2Ni and YH2 upon subsequent dehydrogenation. The reaction enthalpy (ΔH) and entropy (ΔS) of the higher plateau pressure corresponding to Mg2Ni hydride formation are −53.25 kJ mol−1 and −107.74 J K−1 mol−1, respectively. The amorphous/nanocrystalline structure effectively reduces the enthalpy and entropy of Mg2Ni hydride formation, but has little effect on Mg. The activation energy for dehydrogenation of the hydrogenated ribbons is 69 kJ mol−1. This suggests that Mg–Ni–Y with ternary eutectic composition can form an amorphous/nanocrystalline structure by melt spinning, and this nanostructure efficiently improves the thermodynamics and kinetics for hydrogen storage.

Original languageEnglish
Pages (from-to)16644-16653
Number of pages10
JournalInternational Journal of Hydrogen Energy
Volume45
Issue number33
DOIs
StatePublished - 24 Jun 2020

Keywords

  • Hydrogen storage
  • Melt-spun
  • Mg–Ni–Y
  • Nanocrystalline
  • Ternary eutectic
  • Thermodynamics

Fingerprint

Dive into the research topics of 'Microstructural evolution and hydrogen storage proprieties of melt-spun eutectic Mg76.87Ni12.78Y10.35 alloy with low hydrides formation/decomposition enthalpy'. Together they form a unique fingerprint.

Cite this