Journal article

First-principles study on the stability of intermediate compounds of LiBH₄

  • Ohba, Nobuko Toyota Central Research and Development Laboratories, Nagakute, Aichi, Japan
  • Miwa, Kazutoshi Toyota Central Research and Development Laboratories, Nagakute, Aichi, Japan
  • Aoki, Masakazu Toyota Central Research and Development Laboratories, Nagakute, Aichi, Japan
  • Noritake, Tatsuo Toyota Central Research and Development Laboratories, Nagakute, Aichi, Japan
  • Towata, Shin-ichi Toyota Central Research and Development Laboratories, Nagakute, Aichi, Japan
  • Nakamori, Yuko Institute for Materials Research, Tohoku University, Sendai, Japan
  • Orimo, Shin-ichi Institute for Materials Research, Tohoku University, Sendai, Japan
  • Züttel, Andreas Physics Department, University of Fribourg, Switzerland - Department of Environment, Energy and Mobility, EMPA, Dübendorf, Switzerland
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    25.08.2006
Published in:
  • Physical Review B. - 2006, vol. 74, p. 075110
English We report the results of the first-principles calculation on the intermediate compounds of LiBH₄. The stability of LiB₃H₈ and Li₂BnHn (n=5–12) has been examined with the ultrasoft pseudopotential method based on the density-functional theory. Theoretical prediction has suggested that monoclinic Li₂B₁₂H₁₂ is the most stable among the candidate materials. We propose the following hydriding (dehydriding) process of LiBH₄ via this intermediate compound: LiBH₄ <-> 1/2Li₂B₁₂H₁₂+5/6LiH+13/12H₂ <-> LiH+B+3/2H₂. The hydrogen content and enthalpy of the first reaction are estimated to be 10 mass % and 56 kJ/mol H₂, respectively, and those of the second reaction are 4 mass % and 125 kJ/mol H₂. They are in good agreement with experimental results of the thermal desorption spectra of LiBH₄. Our calculation has predicted that the bending modes for the Γ-phonon frequencies of monoclinic Li₂B₁₂H₁₂ are lower than that of LiBH₄, while stretching modes are higher. These results are very useful for the experimental search and identification of possible intermediate compounds.
Faculty
Faculté des sciences et de médecine
Department
Département de Physique
Language
  • English
Classification
Physics
License
License undefined
Identifiers
Persistent URL
https://folia.unifr.ch/unifr/documents/300168
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