Rice University researchers studying hydrogen nano tanks

Researchers at Rice University are studying a new way of potentially storing hydrogen within tiny carbon nano-structures called buckyballs. So far they haven't actually been able to physically test their ideas. They have only done computer simulations to evaluate whether the structures could hold multiple hydrogen atoms. A carbon buckyball made up of 60 carbon atoms can hold up to 58 hydrogen atoms before coming apart. The structure could be scaled up to create larger buckyballs to hold more hydrogen.
The problem is how to actually get the hydrogen into and out of this very strong yet lightweight structure. That may turn out to be an insurmountable problem. Researcher Dr. Boris Yakobson is also looking at different types of nano-structures that might actually be more usable (or usable at all) such as tiny cylinders. Dennis Witmer, a professor at the University of Alaska, doesn't expect this technology to be practical anytime soon.

[Source: Popular Mechanics, thanks to Matt for the tip]