The by- products of the reaction are heat, water in the form of steam, and the electricity produced from the flow of electrons from the anode to the cathode. Figures 1 through 4 illustrate this process for an acid electrolyte fuel cell. Hydrogen gas flows over the anode. Electrons are stripped from the hydrogen and flow through the anode to the external circuit. Hydrogen ions move through electrolyte to cathode.
Electrons move into cathode from load.
Oxygen is introduced to the cathode. The general design of most fuel cells is similar except for the electrolyte. Several different substances have been used as the electrolyte in fuel cells, each with their own advantages and disadvantages. Fuel Cell Demonstration Program. Most individual fuel cells are small in size and produce between 0.5 and 0.9 volts of DC electricity.