A Proton-Conducting Polymer Membrane as Solid Electrolyte – Function and Required Properties

Abstract

Fuel cells are considered as a major energy conversion technology of the future, due to certain inherent advantages of electrochemical conversion processes as compared to thermal combustion processes. Polymer electrolyte fuel cells (PEFCs), operating with hydrogen and air or oxygen at temperatures of around 100 °C, utilize a proton-conducting polymer membrane as solid electrolyte. In this configuration, the proton-conducting polymer membrane has to fulfill several functions: (i) the electrolyte function for surface and bulk ion conduction and (ii) the separator function for gas (reactant) separation. Furthermore, the membrane is part of the gasket system, requiring certain specific mechanical properties. This ensemble of required specifications asks for a comprehensive approach in membrane development for this application. In this short introductory chapter, we summarize some of the general aspects of membrane development for polymer electrolyte fuel cells.