Performance and fuel cell applications of reacted ball-milled MgH(2)/5.3 wt% TiH(2) nanocomposite powders

The present study aimed to enhance the kinetics behavior and destabilize the thermal stability of MgH(2) powder by high-energy milling of Mg powder under 50 bar of H(2) for several hours using Ti-balls as the milling media. The results showed a monotonical increase in Ti content worn off the milling media and introduced into the milled powders. This gradual doping led to homogeneous distribution of fine Ti particles into the Mg/MgH(2) powder matrix without agglomeration or compositional fluctuations at the micro-level. During the activation stage of the powders, achieved at 350 °C/35 bar H(2) prior to hydrogenation kinetics measurements, elemental Ti reacted with H(2) to form fine TiH(2) particles. Our proposed in situ mechanically induced catalyzation approach was found to be mutually beneficial for decreasing the apparent activation energy of decomposition. In addition, introducing 5.3 wt% of TiH(2) to the MgH(2) powder obtained after 50 h led to the achievement of superior enhancement of gas uptake/release kinetics at relatively low temperatures. The nanocomposite MgH(2)/5.3 TiH(2) powder possessed fast hydrogenation/dehydrogenation kinetics behaviors and revealed long cycle lifetimes. This system was successfully employed as a solid-state hydrogen source to charge the battery of a cell-phone device using an integrated Ti-tank/commercial proton exchange membrane-fuel cell system.