Effect of Carbon Material on Hydrogen Storage in Mg/MgH2

Hydrogen is considered an appealing fossil fuel alternative due to its high-energy density, environmental friendliness, and reproducibility, but stable, effective, and secure hydrogen storage continues to be a major challenge. We synthesized magnesium composites doped with 2 wt % graphene, carbon black, or graphite by the mechanical ball milling method. The effects of various carbon materials on the morphology, phase structure, hydrogen uptake and release properties, and thermal decomposition of magnesium-based composites were investigated by XRD, PCT, SEM, and TG-DSC. The experimental findings show that among the various carbon additives, the hydrogen uptake and release abilities of the carbon black modified magnesium composites were the most notable, followed by graphene and graphite. At 623 K, the carbon black modified Mg composites can absorb 5.78 wt % and desorb 5.51 wt % of hydrogen, respectively. Moreover, the incorporation of carbon black greatly reduced the dehydrogenation peak temperature of MgH2. The results indicated that carbon black was instrumental in optimizing the hydrogen storage performance of Mg.