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The company Amminex have invented a technology that can store ammonia (for NOx emission filters, which is their primary business now). They claim this also enables solid hydrogen storage. Indeed, this was their primary research goal. The emission filter business apparently just happened to pick up on one of their side products.

These guys are working on a solution: Solid H-storage.

I believe the relevant slashdot article is here. The link has moved since (and lost relevance, as, judging by the wording of slashdot summary, TFA just announced a presentation), but the guys behind it still have their website (here). But what matters is that the method is not the same. The new method (for suitable values of new) uses an aluminum compound, the one the DTU guys (or whoever) have demonstrated uses ammonia.

Not sure how this got modded "Informative"...

No modern fuel cell systems, particularly for moving vehicles, propose storing hydrogen in gas form. The hydrogen is stored in an inert form (i.e. one that cannot explode on impact, or "leak" hydrogen) - for example in these. The hydrogen is extracted with a catalyst during the power generation process.

Frankly what you're describing is just as (or more) likely to happen with a gasoline-powered vehicle than a modern hydrogen fuel cell design.

I think they describe it quite well, you use a a catalyst, like that guy's hand and he squeezes it out.
http://www.amminex.com/index_files/image355.jpg

I've found another (from June) article here (in french). For a long time people have been talking about ammonia as hydrogen storage, as it's quite high in energy density and is a relatively safe liquid. However, there are issues with gas expansion, pressurization and toxic fumes.

Essentially, these pellets are an ammonia storage system that stores ammonia nearly as efficiently (by weight and volume) as liquid ammonia. The above article says that they are relatively cheap to produce (initial costs of 1 euro/kilogram of material, which translates to roughly $12.88 USD for the energy equivalent of a gallon of gasoline). The article clearly states that the process is reversible, thus the base materials must be reusable. It does not state what the cost is of 'recharging' the pellets. The recharge cost would have to be at least 4x cheaper than production in order for it to be competitive with gasoline. The extraction technique is listed as 'desorption', which I imagine just means heating the pellets up and siphoning the extracted gas off. As for temperatures, and desorption rates, nothing is cited.

It doesn't state specifically how the reaction runs, but that ammonia is extracted from the pellets, which is then run through a standard ammonia converter (at temperatures of around 350 degrees celsius) to extract the hydrogen. It says the reaction runs quickly, so it's able to provide the hydrogen quickly enough.

The Amminex website has slightly more information available by clicking on the "ammonia storage" page, because it's the exact same technology as the hydrogen storage (link here)

It seems that they use a catalyst to break the solid down, and release the hydrogen gas.

At least according to this <sarcasm> informative diagram</sarcasm>