Well “leaks through metal” sort of misconstrues things, “dissolves in metal” or “diffuses in metal” would be a better phrasing. I think a more relevant issue i

Well “leaks through metal” sort of misconstrues things, “dissolves in metal” or “diffuses in metal” would be a better phrasing. I think a more relevant issue is hydrogen embrittlement, it is definitely a problem for many alloys. I don’t think it’s a show stopper for fuel cells though, and it’s an important research topic that’s been worked on a long time