H uptake kinetics of FeTi films coated with Ni

The H2 storage material FeTi can be fully charged through a Ni coating in the course of hours. A mild activation, either by long H2 exposure at RT, or annealing in 35 mbar H2 at 150 °C, leads to a full uptake in minutes. The enhancement of the uptake rate after activation is caused by a reduction of the Ni-oxide surface. Ni does not limit the hydrogen uptake rate once the surface is clean. However, the Ni surface is sensitive to contamination, as for instance by CO adsorbed from air.