Journal article

Hydrogen storage properties of Mg[BH₄]₂

  • Matsunaga, Tomoya EMPA, Department Environment, Energy and Mobility, Abt. 138 “Hydrogen & Energy”, Dübendorf, Switzerland - University of Fribourg, Physics Department, Switzerland
  • Buchter, Florian EMPA, Department Environment, Energy and Mobility, Abt. 138 “Hydrogen & Energy”, Dübendorf, Switzerland - University of Fribourg, Physics Department, Switzerland
  • Mauron, Phillipe EMPA, Department Environment, Energy and Mobility, Abt. 138 “Hydrogen & Energy”, Dübendorf, Switzerland - University of Fribourg, Physics Department, Switzerland
  • Bielmann, Michael EMPA, Department Environment, Energy and Mobility, Abt. 138 “Hydrogen & Energy”, Dübendorf, Switzerland - University of Fribourg, Physics Department, Switzerland
  • Nakamori, Y. Institute for Materials Research, Tohoku University, Sendai Japan
  • Orimo, S. Institute for Materials Research, Tohoku University, Sendai Japan
  • Ohba, N. Toyota Central Research and Development Laboratories, Inc., Nagakute, Aichi, Japan
  • Miwa, K. Toyota Central Research and Development Laboratories, Inc., Nagakute, Aichi, Japan
  • Towata, S. Toyota Central Research and Development Laboratories, Inc., Nagakute, Aichi, Japan
  • Züttel, Andreas EMPA, Department Environment, Energy and Mobility, Abt. 138 “Hydrogen & Energy”, Dübendorf, Switzerland - University of Fribourg, Physics Department, Switzerland
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    18.05.2007
Published in:
  • Journal of Alloys and Compounds. - 2008, vol. 259, no. 1-2, p. 583-588
English Among the large variety of possible complex hydrides only few exhibit a large gravimetric hydrogen density and stability around 40 kJ mol⁻¹H₂. Mg[BH₄]₂ is based on theoretical approaches a complex hydride with an equilibrium hydrogen pressure of approximately 1 bar at room temperature and a hydrogen content of 14.9 mass%. The reaction of Li[BH₄] with MgCl₂ at elevated temperatures was investigated as a possible route to synthesize Mg[BH₄]₂. Li[BH₄] reacts with MgCl₂ at a temperature >523 K at a pressure of 10 MPa of hydrogen, where the product contains LiCl and Mg[BH₄]₂. The desorption pc-isotherm of the product obtained at 623 K shows two flat plateaus, which indicates that the decomposition of the product consists of a two-step reaction. The products of the first and the second decomposition reaction were analyzed by means of X-ray diffraction and found to be MgH₂ and Mg, respectively. The enthalpy for the first decomposition reaction was determined to be ΔH = −39.3 kJ mol⁻¹H₂ by the Van’t Hoff plot of the equilibrium measurements between 563 K and 623 K, which is significantly lower than that for pure Li[BH₄] (ΔH = −74.9 kJ mol⁻¹H₂). However, only the second reaction step (MgH₂ → Mg) is reversible at the condition up to 623 K at 10 MPa of hydrogen.
Faculty
Faculté des sciences
Department
Physique
Language
  • English
Classification
Physics
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License undefined
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Persistent URL
https://folia.unifr.ch/unifr/documents/300800
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