Enhanced hydrogen storage in Mg catalysed by Cu–Ni–Co–Fe quaternary multi-component alloy

Magnesium has been sought after material for hydrogen storage due to its high storage capacity (7.6 wt%) and low cost combined with easy availability. However, sluggish kinetics and high absorption temperature (>300 °C) make it inherently difficult to use in commercial applications such as automobile, which require hydrogen absorption/desorption near ambient temperature and pressure. In this work, Cu–Ni–Co–Fe multi-component transition metal alloy has been used as a catalyst for hydrogen sorption in magnesium. It is seen that the Mg–Cu0.15Ni0.35Co0.25Fe0.25 composite desorbs ∼6 wt% hydrogen at 250 °C at a plateau pressure of ∼0.4 bar and exhibits fast kinetics with ∼3.5 wt% hydrogen absorption in 3 min at 250 °C under 20 bar hydrogen. Synergistic effect of transition elements in a disordered solid solution act as pathway provider for hydrogen and therefore results in reduction in hydrogen desorption temperature, without compromising on the hydrogen storage capacity of the composite. Mg-based composites provide an economic and industrially scalable route for the commercial implementation of hydrogen-fuel cell combined system.