TY - JOUR
T1 - Hydrogen storage properties of Mg[BH4]2
AU - Matsunaga, T.
AU - Buchter, F.
AU - Mauron, P.
AU - Bielman, M.
AU - Nakamori, Y.
AU - Orimo, S.
AU - Ohba, N.
AU - Miwa, K.
AU - Towata, S.
AU - Züttel, A.
N1 - Funding Information:
This study was partially supported by the New Energy and Industrial Technology Development Organization (NEDO), International Joint Research under the “Development for Safe Utilization and Infrastructure of hydrogen” Project (2005-2006), the Swiss Federal Office of Energy (BFE) project “Hydrogen storage in metal- and complex hydrides”, No. 100324 (2003-2006), EU FP6 IP NESSHY “Novel Efficient Solid Storage for Hydrogen, Contract no.:518271 (SES6).
PY - 2008/7/14
Y1 - 2008/7/14
N2 - 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.
AB - 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.
KW - Hydrogen absorbing materials
KW - Thermal analysis
KW - Thermodynamic properties
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U2 - 10.1016/j.jallcom.2007.05.054
DO - 10.1016/j.jallcom.2007.05.054
M3 - Article
AN - SCOPUS:43549092681
VL - 459
SP - 583
EP - 588
JO - Journal of Alloys and Compounds
JF - Journal of Alloys and Compounds
SN - 0925-8388
IS - 1-2
ER -