Ab-initio calculations together with thermodynamic modelling have been applied to M-H-F systems. This work is aimed at characterising thermodynamical properties of solid solutions between light-metal hydrides and fluorides as possible candidates for hydrogen storage applications. The ab-initio periodic CRYSTAL1 code was chosen and different functionals in the DFT framework were used, varying from pure GGA (PBE) to hybrid ones (B3LYP). The complete characterisation of pure and mixed compounds was carried out, from structural to vibrational properties. These computed values were contrasted with experimental data to assess the reliability of the model. A newly implemented algorithm in the CRYSTAL code was used to classify by symmetry all the possible mixed M-H-F configurations, allowing the gain of computational resources.2 Enthalpies of mixing derived from quantum-mechanical calculations were used to fit and integrate data extracted from well-known thermodynamical databases (such as JANAF3) within different models for solid solutions treatment in the CALPHAD scheme.4 Excess energy and full thermodynamic characterisation will demonstrate that this computational approach can be useful to predict the mixing of several compounds, ranging from Al and Mg hydrides to borohydrides (LiBH4, Ca(BH4)2 and others). In this presentation, the methodological aspects and the most relevant results will be discussed in details. This work is part of the European FP7 Project FLYHY “Fluorine Substituted High Capacity Hydrides for Hydrogen Storage at low Working Temperatures”.5 References 1. R. Dovesi, V. R. Saunders, C. Roetti, R. Orlando, C. M. Zicovich-Wilson, F. Pascale, B. Civalleri, K. Doll, N. M. Harrison, I. J.Bush, P. D’Arco, M. Llunell, CRYSTAL2006 User's Manual; www.crystal.unito.it, University of Torino: Torino, 2006. 2. A. Meyer, P. D'Arco, R. Orlando, C. M. Zicovich-Wilson, L. Maschio, R. Dovesi, J. Chem. Phys. (2010), submitted. 3. Chase, M. W., NIST-JANAF Thermochemical Tables. J. Phys. Chem. Ref. Data Monograph 9 4. L. Kaufman, CALPHAD-Computer Coupling of Phase Diagrams and Thermochemistry. Pergamon: Oxford, 1977. 5. www.flyhy.eu
A computational study of thermodynamic properties of M-H-F systems for hydrogen storage applications
CORNO, MARTA;PINATEL, EUGENIO RICCARDO;UGLIENGO, Piero;BARICCO, Marcello
2010-01-01
Abstract
Ab-initio calculations together with thermodynamic modelling have been applied to M-H-F systems. This work is aimed at characterising thermodynamical properties of solid solutions between light-metal hydrides and fluorides as possible candidates for hydrogen storage applications. The ab-initio periodic CRYSTAL1 code was chosen and different functionals in the DFT framework were used, varying from pure GGA (PBE) to hybrid ones (B3LYP). The complete characterisation of pure and mixed compounds was carried out, from structural to vibrational properties. These computed values were contrasted with experimental data to assess the reliability of the model. A newly implemented algorithm in the CRYSTAL code was used to classify by symmetry all the possible mixed M-H-F configurations, allowing the gain of computational resources.2 Enthalpies of mixing derived from quantum-mechanical calculations were used to fit and integrate data extracted from well-known thermodynamical databases (such as JANAF3) within different models for solid solutions treatment in the CALPHAD scheme.4 Excess energy and full thermodynamic characterisation will demonstrate that this computational approach can be useful to predict the mixing of several compounds, ranging from Al and Mg hydrides to borohydrides (LiBH4, Ca(BH4)2 and others). In this presentation, the methodological aspects and the most relevant results will be discussed in details. This work is part of the European FP7 Project FLYHY “Fluorine Substituted High Capacity Hydrides for Hydrogen Storage at low Working Temperatures”.5 References 1. R. Dovesi, V. R. Saunders, C. Roetti, R. Orlando, C. M. Zicovich-Wilson, F. Pascale, B. Civalleri, K. Doll, N. M. Harrison, I. J.Bush, P. D’Arco, M. Llunell, CRYSTAL2006 User's Manual; www.crystal.unito.it, University of Torino: Torino, 2006. 2. A. Meyer, P. D'Arco, R. Orlando, C. M. Zicovich-Wilson, L. Maschio, R. Dovesi, J. Chem. Phys. (2010), submitted. 3. Chase, M. W., NIST-JANAF Thermochemical Tables. J. Phys. Chem. Ref. Data Monograph 9 4. L. Kaufman, CALPHAD-Computer Coupling of Phase Diagrams and Thermochemistry. Pergamon: Oxford, 1977. 5. www.flyhy.eu
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