Origin of degradation in the reversible hydrogen storage capacity of V 1-xTix alloys from the atomic pair distribution function analysis

Hyunjeong Kim, Kouji Sakaki, Hiroshi Ogawa, Yumiko Nakamura, Jin Nakamura, Etsuo Akiba, Akihiko Machida, Tetsu Watanuki, Thomas Proffen

Research output: Contribution to journalArticle

26 Citations (Scopus)

Abstract

Reduction in reversible hydrogen storage capacity with increasing hydrogenation and dehydrogenation cycle number is observed in numerous hydrogen storage materials, but the mechanism behind this unfavorable change has not been elucidated yet. In this study, we have investigated the development of structural defects or disorders in V1-xTixH2, x = 0, 0.2, and 0.5, during the first 15 hydrogen absorption and desorption cycles using the atomic pair distribution function (PDF) analysis of synchrotron X-ray total scattering data to find out the possible structural origin of the poor cyclic stability of V1-xTix alloys. While pure vanadium shows no significant change in the PDF, alloy samples subject to several hydrogenation and dehydrogenation cycles display fast decaying of the PDF profile due to a progressive increase in the PDF peak width with increasing r. This r-dependent PDF peak broadening effect becomes stronger with cycle number. Molecular dynamics (MD) simulations demonstrated that dislocation defects explain characteristic features in our experimental PDFs very well and suggested that a large number of dislocations are formed during hydrogen cycling. We found there is a close relation between the reduced amount of the reversible hydrogen content of V0.8Ti0.2 and the amount of generated dislocations. On the basis of the PDF analysis results, a possible mechanism behind degradation in the reversible hydrogen storage capacity of V1-xTix is discussed.

Original languageEnglish
Pages (from-to)26543-26550
Number of pages8
JournalJournal of Physical Chemistry C
Volume117
Issue number50
DOIs
Publication statusPublished - Dec 19 2013

All Science Journal Classification (ASJC) codes

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

Fingerprint Dive into the research topics of 'Origin of degradation in the reversible hydrogen storage capacity of V <sub>1-x</sub>Ti<sub>x</sub> alloys from the atomic pair distribution function analysis'. Together they form a unique fingerprint.

  • Cite this

    Kim, H., Sakaki, K., Ogawa, H., Nakamura, Y., Nakamura, J., Akiba, E., Machida, A., Watanuki, T., & Proffen, T. (2013). Origin of degradation in the reversible hydrogen storage capacity of V 1-xTix alloys from the atomic pair distribution function analysis. Journal of Physical Chemistry C, 117(50), 26543-26550. https://doi.org/10.1021/jp408766r