Raghunathan Rengasamy

The limited availability of conventional energy carriers has increased the demand for renewable energy sources to cater to the ever increasing energy demand. The present chapter focusses on phosphoric acid fuel cells (PAFCs) detailing their working principles and application potential. The different materials used in PAFCs, including electrolyte, catalysts and bipolar plates and their importance in the ultimate performance are summarized. The degradation behavior due to acid leaching which affect several components of the cell is outlined. Researchers’ contributions towards early identification of degradation of catalyst and catalyst support in particular due to the presence of excess quantity of phosphoric acid, is also described. The importance of having anticorrosive coatings on bipolar plates is outlined in view of achieving life enhancement of the cell operation. Significant work has been carried out in PAFC modeling (1D–3D, steady state and dynamic models) and these are reviewed. The important design considerations during scale-up such as gasket selection and its arrangement, planarity of electrodes, fabrication method of membrane electrode assemblies (MEAs), thermal stress management etc. are described in detail. The chapter outlines various applications explored from power ratings of 20–500kW and also future requirements to be addressed in material as well as engineering issues.