hydrogen fuel cell 
A fuel cell is an electrochemical device that converts chemical energy from hydrogen and oxygen into electricity. In most applications, electricity from fuel cells powers electric motors at each wheel. Fuel-cell vehicles currently in service use compressed hydrogen to blend with oxygen from the atmosphere. To move even a light vehicle around, a number of fuel cells are connected in series to provide adequate operating voltage.

Although electrolyzing water can produce hydrogen fuel, it's an expensive process, and the operating range is limited. Hydrogen fuel can also be reformed from gasoline, methanol, or even borax, and there's plenty of research in the fuel-cell field since hydrogen can lessen our dependence on fossil fuels.

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