Question

What is the solid electrolyte called in a fuel cell?

What is the main reason that fuel cells do not produce the theoretical voltage of 1.23 volts?

Answer 1

There are many types of electrolytes in fuel cells. Which of these two is solid, one is called Proton Exchange Membrane (PEM) and other is Solid oxide.

In fuel cell the solid electrolyte is called Solid oxide. Solid Oxide fuel cells (SOFC) use a hard, ceramic compound of metal as electrolyte. These ceramic compounds are calcium or zirconium oxides.

What is the main reason that fuel cells do not produce the theoretical voltage of 1.23 volts?

At anode            2H₂ ----> 4H⁺ + 4e                         Eo = 0 V

At cathode      O₂ + 4H⁺ + 4e- ----> 2 H O               E^o = 1.23V

E^o cell = E^o ox + E^o red

E^o = 0 V + 1.23V = 1.23V

The theoretically maximum voltage that can be produced from the fuel cell is 1.23 volts, but it is impossible to achieve due to internal resistance, voltage losses as heat and diffusion losses.