Effectiveness of crystallitic carbon from coal as milling aid and for hydrogen storage during milling with magnesium

► Carbon from coal acted as dispersant, lubricant and milling media for Mg milling. ► The Mg easily hydrided into β-MgH2 and γ-MgH2 during milling under hydrogen. ► Nanocomposites with hydrogen capacity of 6.67 wt.% were prepared by 3 h of milling. ► CH dangling bonds made some contribution to hydrogen capacity of the composites.