dAlH2Orean: An RC car that runs on aluminum soda can tabs (w/ video)

The problem is, once the aluminium is turned into aluminium hydroxide, you have to turn it back into aluminium somehow.

The production of aluminium from its oxides is a very energy intensive process because it has to be done through molten electrolysis, which is why soda cans are recycled instead of burned or dumped in landfills.

The energy efficiency is just 50% and combined with the efficiency of the fuel cell, you will achieve less then 25% total efficiency. And you still need to produce the electricity for the electrolyzer somehow. All in all, that makes the idea a rather poor one.

There are some attractive points: an aluminum-aluminum hydroxide energy cycle would be a lot cleaner than the current fossil fuel-air cycle (no emissions if you get electricity from solar or wind); aluminum production from oxides is well established technology, and the engine waste would be very pure feedstock; it would be simple mechanics to feed the reaction from aluminum wire or ribbon off of a spool; most current internal combustion engines can be modified to run on hydrogen... yeah. This has possibilities.

So you think it will be cleaner to have people loading aluminum and sodium hydroxide into their cars and then returning the spent aluminum oxide back to a plant to have it reduced back to aluminum. Do you really want people handling concentrated NaOH or a mixture or aluminum oxide and NaOH? What will the gas tank be made of so that it doesn't corrode over time? How will the reaction be controlled and adjusted to the power demands of the car? It's not like this is even new technology its more of a science fair project for engineers than anything. Not practical at all.

If you want to run a fuel cell car its makes much more sense (thermodynamically) to use Hydrogen (compressed or stored in a metal substrate) or a liquid fuel that can be reformed on site or directly oxidized at the fuel cell like a direct methanol fuel cell.