A hydrogen fuel cell is a device that converts hydrogen and oxygen into electricity. While batteries have all their energy stored internally and run out of power when the fuel is gone, hydrogen fuels cells continue to make electricity for as long as hydrogen is supplied. Hydrogen fuel cells are being developed to power automobiles, but other applications for them also exist.http://auto.howstuffworks.com/fuel-efficiency/alternative-fuels/fuel-cell.htm

Hydrogen fuel cells convert stored chemical energy directly into electrical energy. They contain a divider called an electrolyte in the center or at their core that separates electrodes from one another and diverts the newly created electricity through an electrical circuit. Before going through the circuit, the electrons must also pass through a bipolar plate, which collects the charge and helps to raise the voltage to a satisfactory level.http://auto.howstuffworks.com/fuel-efficiency/alternative-fuels/fuel-cell.htm

If pure hydrogen is in short supply, gasoline can be converted into hydrogen and used to run the fuel cell. However, it is a complex and inefficient process, and the gas must be refined and cleaned to a significant degree before it can be used to power a hydrogen fuel cell.http://auto.howstuffworks.com/fuel-efficiency/alternative-fuels/fuel-cell.htm