Catalyzed KSiH3 as a Reversible Hydrogen Storage Material

Published

November 1, 2016

Author(s)

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

Abstract

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.

Citation

Journal of Materials Chemistry A

Volume

4

Issue

48

Pub Type

Journals

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Keywords

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

Citation

Janot, R. , Tang, W. , Clemencon, D. and Chotard, J. (2016), Catalyzed KSiH₃ as a Reversible Hydrogen Storage Material, Journal of Materials Chemistry A, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=921490 (Accessed October 14, 2025)