The PEMFC (polymer electrolyte membrane fuel cell)
is a kinds of electro – chemical system to exchange chemical potential energy
of gases, especially hydrogen and oxygen, to electrical energy. The system
always makes water as a reactant of gases or condensation of slow humidity of
gases. Hydrogen gas is diffused from channel to gas diffusion layer. And when
it touches the anode catalyst layer, then hydrogen is ionized and generate
electron. Membrane has high proton conductivity but low electrical
conductivity. So the electron does not move toward membrane and it moves toward
GDL and outer circuit. On the other hand, hydrogen ion passes through the membrane
and at the cathode side catalyst layer, hydrogen ion, oxygen, and electron meet
and generate water and electricity.