Effect of High-Energy Ball Milling and Additives of Ti and Multiwalled Carbon Nanotubes on the Hydrogen Absorption of AM60 Magnesium Alloy

Abstract

Hydrogen storage materials are critical for sustainable energy applications. Magnesium is a promising material for hydrogen storage due to its high volumetric and gravimetric hydrogen storage capacities. However, its application in fuel cells is hindered by slow hydrogen sorption kinetics. This study aims to investigate the hydrogen absorption of a commercial AM60 alloy catalyzed by Ti and multiwalled carbon nanotubes additives, as well as the microstructural changes induced by high-energy ball milling (HEBM). The results show that the HEBM of the AM60 alloy reduces the particle size to 22 μm, introducing microvoids and porosity between the particles, which increase the total pore volume and hydrogen absorption capacity from 1.5 to 4 wt%. Catalyzing the AM60 alloy with a 5 wt% Ti increases absorption to 4.35 wt%. The AM60-5 wt% MWCNT sample shows higher surface area of 34 m² g⁻¹, highest hydrogen absorption capacity of 6.2 wt%, and the fastest hydrogen absorption rate. The novelty of this study lies in demonstrating the synergistic effects of HEBM and MWCNT additives, thereby establishing a practical approach for optimizing magnesium-based materials for hydrogen storage.