PNNL

Abstract

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