Potassium silanide (KSiH3): a reversible hydrogen storage material |
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Authors: | Chotard Jean-Noël Tang Wan Si Raybaud Pascal Janot Raphaël |
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Affiliation: | Laboratoire de Réactivité et Chimie des Solides, UMR 6007 CNRS Université de Picardie Jules Verne, 33 rue St Leu, 80039 Amiens, France. |
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Abstract: | KSi silicide can absorb hydrogen to directly form the ternary KSiH3 hydride. The full structure of α‐KSiD3, which has been solved by using neutron powder diffraction (NPD), shows an unusually short Si? D lengths of 1.47 Å. Through a combination of density functional theory (DFT) calculations and experimental methods, the thermodynamic and structural properties of the KSi/α‐KSiH3 system are determined. This system is able to store 4.3 wt % of hydrogen reversibly within a good P–T window; a 0.1 M Pa hydrogen equilibrium pressure can be obtained at around 414 K. The DFT calculations and the measurements of hydrogen equilibrium pressures at different temperatures give similar values for the dehydrogenation enthalpy (≈23 kJ mol?1 H2) and entropy (≈54 J K?1 mol?1 H2). Owing to its relatively high hydrogen storage capacity and its good thermodynamic values, this KSi/α‐KSiH3 system is a promising candidate for reversible hydrogen storage. |
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Keywords: | density functional calculations hydrogen storage hydrogenation silanides thermodynamics |
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