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Catalyzed KSiH3 as a Reversible Hydrogen Storage Material



Raphael Janot, Wan Si NMN Tang, Damien Clemencon, Jean-Noel Chotard


Solid-state hydrogen storage through the reversible formation of metallic hydrides is a key issue for the development of hydrogen as an energy vector. Herein reports the hydrogen storage performances of the KSiH3 silanide phase ball-milled with NbF5 as a catalyst. The kinetics of hydrogen absorption/desorption are strongly enhanced by the addition of catalyst as revealed by the large decrease of activation energies for both the adsorption and desorption reactions. No disproportionation phenomenon is observed, indicating that the reaction between KSiH3 and KSi is perfectly reversible with an experimental hydrogen storage capacity of about 4.1 wt.% H2. The thermodynamic properties of this KSi/KsiH3 equilibrium were than reinvestigated by plotting PCI curves from 90°C to 130°C: an enthalpy of 24.3 kK/mol-1 H2 and a low entropy change of 59.5 J.K-1.molu-1 H2 are found. This low entropy variation is related to the high mobility of the H atoms in the α-KsiH3 phase, as recently demonstrated by Quasi-Elastic Neutron Scattering (QENS) experiments.
Journal of Materials Chemistry A


complex hydrides, alkali silanide, alkali silicide, catalysis, kinetics, thermodynamics


Janot, R. , Tang, W. , Clemencon, D. and Chotard, J. (2016), Catalyzed KSiH<sub>3</sub> as a Reversible Hydrogen Storage Material, Journal of Materials Chemistry A, [online], (Accessed April 20, 2024)
Created October 31, 2016, Updated October 12, 2021