Hydrogen storage behavior of Mg@Mg2Si and Mg@Mg17Al12 alloys with additions of carbon allotropes and talc

Abstract

Mg based hydrogen storage alloys containing catalyzing particles are frequently studied because the catalysis is one of possible ways how to speed-up effectively the hydrogen sorption kinetics. Ball milled alloys Mg@Mg2Si and Mg@Mg17Al12 are studied in the present paper. They consist of Mg grains, which hydrogen storage performance is catalyzed by the Mg2Si and Mg17Al12 particles. Graphite, amorphous carbon (carbon black) and magnesium silicate monohydrate (talc) were added to facilitate the fine ball milling. It was found that addition 0.14 wt% of amorphous carbon to Mg@Mg2Si shows the best hydrogen sorption kinetics and the highest sorption capacity of about 6 wt% H2. A weak destabilization of MgH2 hydride by Mg2Si and Mg17Al12 was observed. New technique of equilibrium hydrogen pressure estimation was proposed.