My understanding is that there has been a lot of advance in storing hydrogen in sponge like materials to which it weakly bonds in a hydride form and can be easily extracted in the vehicle using a catalyst.
In many ways it is like a ni-cad battery only instead of extracting electricty one extracts hydrogen, and then periodically re adds it.
The major problems are weight and size (currently about 3x as big as a gas tank and 6x as heavy), cost (metals used as the sponge may be expensive not to mention the catalyst), and safety.
The big push is for the tank to store about 50% of its weight in hydrogen. At that point you probably have something commercially feasible.
Yes, new materials are being found all the time. If I can find this, it is an article from just yesterday. Yes, here we go.
In a new paper researchers at the National Institute of Standards and Technology’s Center for Neutron Research (NCNR) have demonstrated that a novel class of materials could enable a practical hydrogen fuel tank.
A research team from NIST, the University of Maryland and the California Institute of Technology studied metal-organic frameworks (MOFs). One of several classes of materials that can bind and release hydrogen under the right conditions, they have some distinct advantages over competitors.
In principle they could be engineered so that refueling is as easy as pumping gas at a service station is today, and MOFs don’t require the high temperatures (110 to 500 C) some other materials need to release hydrogen.
In particular, the team examined MOF-74, a porous crystalline powder developed at the University of California at Los Angeles. MOF-74 resembles a series of tightly packed straws comprised of mostly carbon atoms with columns of zinc ions running down the inside walls. A gram of the stuff has about the same surface area as two basketball courts.