Calorimetric study of the PEMFC

A calorimeter has been constructed and used to measure the total heat production of a single polymer electrolyte fuel cell that is operated on hydrogen and oxygen at 50 °C and 1 bar. The cell had a SolviCore Catalyst Coated Backing and a Nafion RE112 membrane. We report that the total heat production plus the power production corresponds to the enthalpy of formation of water for cell potentials above 0.55 V. There is a linear decrease in the total reaction enthalpy as function of the cell potential for these lower cell potentials. This trend is observed independently of current density and membrane thickness. We propose that the main cause of power loss at high current densities is due to hydrogen peroxide formation. The total heat production was decomposed into reversible and irreversible effects (ohmic and non-ohmic). We show that it is possible to determine the overpotential of an electrode from its thermal signature.