Batteries = TOO MUCH WEIGHT & DANGER
If, in the distant future, this were to be useful - you would need to do it via fuel cell technology. The problem, within the limits of TODAY'S capabilities, is that you simply can't carry enough H2. I've read some interesting research on microfibers that allow you to trap more H2 molecules, hence increasing the amount of H2 you can carry in one cylinder. Still, I think it will be 20-30 years before something efficient is put together.