title: Potassium silanide (KSiH3): a reversible hydrogen storage material.
abstract: KSi silicide can absorb hydrogen to directly form the ternary KSiH(3) hydride. The full structure of α-KSiD(3), 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-KSiH(3) system are determined. This system is able to store 4.3 wt% of hydrogen reversibly within a good P-T window; a 0.1 MPa 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) H(2)) and entropy (≈54 J K(-1) mol(-1) H(2)). Owing to its relatively high hydrogen storage capacity and its good thermodynamic values, this KSi/α-KSiH(3) system is a promising candidate for reversible hydrogen storage.
authors.affiliation: Laboratoire de Réactivité et Chimie des Solides, UMR 6007 CNRS Université de Picardie Jules Verne, 33 rue St Leu, 80039 Amiens, France.
authors.forename: Jean-Noël
authors.initials: JN
authors.lastname: Chotard
authors.forename: Wan Si
authors.initials: WS
authors.lastname: Tang
authors.forename: Pascal
authors.initials: P
authors.lastname: Raybaud
authors.forename: Raphaël
authors.initials: R
authors.lastname: Janot