H2 is difficult to store. To store enough of it to be useful it needs to be either very high pressure or so cold is becomes a liquid. Because it is so small, i

H2 is difficult to store. To store enough of it to be useful it needs to be either very high pressure or so cold is becomes a liquid. Because it is so small, it tends to leak through most materials and can cause them to become brittle (http://en.wikipedia.org/wiki/Hydrogen_embrittlement http://en.wikipedia.org/wiki/Hydrogen_embrittlement) but it is not "extremely corrosive". Thick carbon fiber tanks can store H2 at high pleasure so that with the efficiency of an electric drive-train, the car has good range.