Hydrogen sorption properties of ternary intermetallic Mg–(Ir,Rh,Pd)–Si compounds

Hydrogen gas phase and electrochemical hydriding/dehydriding behavior of new ternary Mg–(Ir,Rh,Pd)–Si intermetallic compounds with compositions appropriate for hydrogen storage is investigated. The intermetallic compound with the highest magnesium content (Mg15Ir5Si2 with channel-like structure) reveals the highest electrochemical hydrogen capacity, but generally the capacities of all intermetallics studied are low (≤60 mAh/g discharge capacities and ≤0.8 wt.% H-gas phase capacity). Refining the particle size and microstructure does not result in significant H-capacity increase. The present study shows that the low H-capacity and unsatisfactory hydriding kinetics measured are most probably due to the insufficient channel size of the crystal structures.