Basic Principles of SOFC

H2 molecule releases two electrons with an electrical potential (i.e., voltage) of 1.055 volt at 800 C in an open circuit. 

Theoretically all the combustible materials can serve as a fuel to the SOFC via the direct electrochemical oxidation on the anode. Table 1 lists a number of fuel reactions with AG° (i.e., the change in the Gibbs free energy) and AH° (the change in the enthalpy), E° (theoretically reversible potential or voltage), and the fuel cell efficiency. Fuel cell efficiency is defined as  

The anode electrode should (i) exhibit catalytic activity for electrochemical oxidation (ii) possess electrical conductivity and (iii) show stability in reducing 

In contrast to the reducing environment of the anode, the cathode in the oxidizing environment must perform the reduction of O2 to over a wide range of O2 partial pressures. Therefore, the cathode should have a good electrical conductivity to transport the electron to the adsorbed oxygen. 

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