Degradation mechanism against hydrogenation cycles in Mg 2-xPrxNi4 (x = 0.6 and 1.0)

K. Sakaki, N. Terashita, H. Kim, E. H. Majzoub, A. Machida, T. Watanuki, S. Tsunokake, Y. Nakamura, Etsuo Akiba

Research output: Contribution to journalArticle

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Abstract

A long cycle life of metal hydrides is paramount for applications. We present an investigation of the degradation mechanism against hydrogenation cycles in Mg2-xPrxNi4 (x = 0.6 and 1.0). Mg1.0Pr1.0Ni4 shows significant degradation and loss of capacity after only a few cycles. In stark contrast, Mg 1.4Pr0.6Ni4 did not show any reduction of hydrogen storage capacity until 100 cycles at 313 K. The peak broadening of X-ray diffraction (XRD) patterns and accumulation of lattice strain were observed concomitantly with an increase of hydrogenation cycles only in Mg 1.0Pr1.0Ni4. These changes were not observed in Mg1.4Pr0.6Ni4. In pair distribution function (PDF) patterns, r-dependent peak broadening was observed and it became significant with an increasing number of cycles in Mg1.0Pr 1.0Ni4, suggesting an increase of the dislocation density. Mg1.4Pr0.6Ni4 showed higher hardness and more pulverization upon hydrogenation than Mg1.0Pr1.0Ni 4. These results suggest that the dominant mechanism, the stress induced by hydrogen occupation release, must change from the formation of dislocations to pulverization by increasing the Mg content of the alloy. We discuss how this leads to better cycling properties.

Original languageEnglish
Pages (from-to)6697-6705
Number of pages9
JournalJournal of Physical Chemistry C
Volume118
Issue number13
DOIs
Publication statusPublished - Apr 3 2014

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Hydrogenation
hydrogenation
degradation
Degradation
cycles
Hydrogen storage
Hydrides
Diffraction patterns
Distribution functions
Life cycle
Hydrogen
Metals
Hardness
X ray diffraction
metal hydrides
hydrogen
occupation
diffraction patterns
hardness
distribution functions

All Science Journal Classification (ASJC) codes

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

Cite this

Sakaki, K., Terashita, N., Kim, H., Majzoub, E. H., Machida, A., Watanuki, T., ... Akiba, E. (2014). Degradation mechanism against hydrogenation cycles in Mg 2-xPrxNi4 (x = 0.6 and 1.0). Journal of Physical Chemistry C, 118(13), 6697-6705. https://doi.org/10.1021/jp500855d

Degradation mechanism against hydrogenation cycles in Mg 2-xPrxNi4 (x = 0.6 and 1.0). / Sakaki, K.; Terashita, N.; Kim, H.; Majzoub, E. H.; Machida, A.; Watanuki, T.; Tsunokake, S.; Nakamura, Y.; Akiba, Etsuo.

In: Journal of Physical Chemistry C, Vol. 118, No. 13, 03.04.2014, p. 6697-6705.

Research output: Contribution to journalArticle

Sakaki, K, Terashita, N, Kim, H, Majzoub, EH, Machida, A, Watanuki, T, Tsunokake, S, Nakamura, Y & Akiba, E 2014, 'Degradation mechanism against hydrogenation cycles in Mg 2-xPrxNi4 (x = 0.6 and 1.0)', Journal of Physical Chemistry C, vol. 118, no. 13, pp. 6697-6705. https://doi.org/10.1021/jp500855d
Sakaki K, Terashita N, Kim H, Majzoub EH, Machida A, Watanuki T et al. Degradation mechanism against hydrogenation cycles in Mg 2-xPrxNi4 (x = 0.6 and 1.0). Journal of Physical Chemistry C. 2014 Apr 3;118(13):6697-6705. https://doi.org/10.1021/jp500855d
Sakaki, K. ; Terashita, N. ; Kim, H. ; Majzoub, E. H. ; Machida, A. ; Watanuki, T. ; Tsunokake, S. ; Nakamura, Y. ; Akiba, Etsuo. / Degradation mechanism against hydrogenation cycles in Mg 2-xPrxNi4 (x = 0.6 and 1.0). In: Journal of Physical Chemistry C. 2014 ; Vol. 118, No. 13. pp. 6697-6705.
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AU - Machida, A.

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AU - Tsunokake, S.

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