Hydrogen Storage Performance of AZ31 Magnesium Alloy Catalyzed by Vanadium and Carbon Black

Magnesium‐based alloys are promising solid‐state hydrogen storage materials, but their practical applications remain limited by sluggish kinetics and high operating temperatures. This study investigates the combined effects of low‐content vanadium (V) and carbon black (CB) on commercial AZ31 alloy prepared via high‐energy ball milling. The low V content of 0.5 wt.% provides catalytic activity while minimizing gravimetric capacity loss, whereas CB assists powder refinement and suppresses particle agglomeration when combined with V. The AZ31 + 3CB control sample achieves 6.09 wt.% at 375 °C, confirming the individual contribution of CB. Among the investigated compositions, AZ31 + 0.5V + 3CB exhibits the highest absorption capacity of 6.46 wt.% at 375 °C, compared with 5.11 wt.% for pristine AZ31. Kissinger analysis shows that the apparent activation energy decreases from 144.990 kJ mol ⁻¹ for AZ31 to 104.372 kJ mol ⁻¹ for AZ31 + 0.5V + 3CB, while the time required to reach 90% capacity shortens from 1956 to 1062s. Furthermore, the composition maintained good cyclic stability, with 94.2% capacity retention after 50 cycles. These results demonstrate that the optimized V/CB comodified AZ31 system enhances hydrogen storage kinetics through CB‐assisted microstructural refinement and V‐assisted catalytic activation.