The Thermodynamic Efficiency of Fuel Cells

Abstract

The methods of chemical thermodynamics prove useful in the study of fuel cells despite the fact that normally only equilibrium properties can be discussed. There are two main avenues which can be explored. First, a study of the thermodynamics of the Carnot cycle for a perfectly reversible heat engine will show that there is a limiting efficiency which restricts the usefulness of any heat engine (as was mentioned in the previous chapter), and this can be compared with the possible efficiency of a fuel cell. Secondly, the electromotive force of a fuel cell (that is the maximum potential difference across the electrodes of a cell when no current is being taken from it) can be calculated by considering the electrochemical equilibrium set up when a fuel cell is studied potentiometrically.