First-principles prediction of possible synthesis of li-fe based complex hydride Li4FeH6

Shigeyuki Takagi, Tamio Ikeshoji, Toyoto Sato, Katsutoshi Aoki, Shin Ichi Orimo

Research output: Contribution to journalArticle

8 Citations (Scopus)

Abstract

The crystal and electronic structures, and thermodynamic stability of hypothetical complex hydride Li4FeH6 were examined using first-principles calculations. We found that the hydride occurs in a K 4CdCl6-type structure with space group R-3c (No. 167), which is the same as that reported for Na4RuH6. The calculated enthalpy change of the reaction, 4LiH + Fe + H2 Li4FeH6, is - 54 kJ/mol H2. Given that Fe does not form any stable binary compounds with both Li and H, Li4FeH6 could be the most stable phase among the compounds consisting of Li, Fe and H. Using a calculated entropy change of -115 J/mol H2 • K, the equilibrium pressure under 773 K is estimated to be 24 MPa. The electronic structure illustrates that four Li atoms donate a total of four electrons per formula unit to the FeH6 octahedron, forming an ionic configuration of Li+4[FeH6] 4-. The complex hydride reported here has the hieher hvdrocen gravimetric density, a value of 6.7 mass%. than other Fe-based complex hydrides ever reported. and thus would be of interest in terms of hydrogen storage

Original languageEnglish
Pages (from-to)604-608
Number of pages5
JournalNippon Kinzoku Gakkaishi/Journal of the Japan Institute of Metals
Volume77
Issue number12
DOIs
Publication statusPublished - 2013 Dec

Keywords

  • Complex hydride
  • Crystal structure
  • Electronic structure
  • First-principles calculations
  • Hydrogen storage
  • Iron
  • Lithium

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Mechanics of Materials
  • Metals and Alloys
  • Materials Chemistry

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