Hydrogen fuel cells

Reaction at the negative electrode

Oxidation

2H_{2 (g)} → 4H⁺_(g) + 4e^-

Reaction at the positive electrode

Reduction

O_{2 (g)} + 4H⁺_(aq) + 4e^- → 2H₂O_(l)

Overall reaction

2H₂ + O₂ → 2H₂O

Compare Hydrogen fuel cells with rechargeable batteries

Hfc does not release CO2 but electricity for rb may be generated with fossil fuels

Hfc will travel further without refueling and get refueled faster

Hfc do not get less efficient overtime but rb need to be replaced

H2 is an explosive gas and hard to store safely but no dangerous fuels in rb

Hfc producce lower pd than rb

Hfc more expensive to make and repair than rb