I read the first one you posted.
Creating hydrogen from aluminum isn’t difficult, and can be done in your kitchen at home (that engaget article is incorrect on that point, it is relatively easy to do). Like I said above it’s been done over and over again. Hundreds of experiments have been done using different types and combinations of stuff. In all of them aluminum soaks up the oxygen atoms and releases hydrogen. The aluminum is spent.
Creating hydrogen from water and aluminum is nothing new. There’s papers going back to the early 1970’s on the topic. The problem has always been one of economics; it ends up costing far more to create the hydrogen than it does other fuels.
Every last one to date creates alumina or some oxidized compound in the end, which can’t be used again. The energy cost of making aluminum is vastly higher than the energy you’d get by using it as a reactor agent, so it’s a net loss equation, just as it always has been with using water as a reaction mass using other methods.
A more efficient means of using aluminum is to create energy is to combine it with another substance, like potassium perchlorate, and burn it. From firecrackers to space shuttles, that stuff is proven to make massive amounts of energy. Sure, it’s in the form of heat and gas, but still, makes a buttload of energy.
Aluminum is horribly energy expensive to make. Something like 35-42% of the cost of making aluminum is electricity. 12,000 to 15,000 kWh to make a metric ton. End costs are something like $1700+ per metric ton for manufacturing. Plus energy costs of turning that in to a specific grain size of dust. If we begin using it as a fuel source that’ll just continue to inflate costs further.
If they found a new alloy that doesn’t oxidize, that’d be something, but only if it’s truly reusable. So far all of human kinds attempts at solving that have failed.