Electrical Work and Thermoneutral Enthalpy Voltage

The standard electrical work, zFjP, is related to the standard Gibbs free enthalpy by  

Usually, the standard Gibbs free enthalpy is calculated by the stoichiometric sums of the standard enthalpies of formation and the standard entropies  

Oxidant(s)-He - reductant(s) Standard potential ° versus standard H2 electrode (V) 

that is, ArG 0, the cell reaction occurs spontaneously and the cell delivers electrical energy. This is utilized in H2/O2 fuel cells  

Calculation of ARGjgg by Eq. (6.19.16) yields 237.2kjmol (= 2 x 1.23 V X 96 485 A s mol ). The term TAr has a negative value of 48.7 kJ mol and represents the heat released by the system, which cannot be exploited as electrical work (details in Juettner, 2007). 

---