A graphite wafer was implanted with Mg+ to produce a uniform Mg concentration. Subsequent H+ implantation covered the Mg+-implanted and non-implanted regions. Ion-beam analysis showed a higher H retention in graphite embedded with Mg than in regions without Mg. A small amount of H diffused out of the H+-implanted graphite during thermal annealing at up to 300C. However, significant H release from the region implanted with Mg+ and H+ ions occurs at 150C; further release was also observed at 300C. The results suggested that there were efficient H trapping centers and fast pathways for H diffusion in the Mg+-implanted graphite, which may prove highly desirable for reversible H storage.

Hydrogen Behavior in Mg+-Implanted Graphite. W.Jiang, V.Shutthanandan, Y.Zhang, S.Thevuthasan, W.J.Weber, G.J.Exarhos: Journal of Materials Research, 2006, 21[4], 811-5