Engineering the Ionic Polymer Phase Surface Properties of a PEM Fuel Cell Catalyst Layer

Abstract

© The Electrochemical Society. During high power density operations, the performance of polymer electrolyte membrane fuel cells (PEMFCs) is limited by high water saturation levels in the cathode catalyst layer due to high wettability of the ionic polymer phase. A new heat treatment was used to create and permanently lock-in the surface structure of a biphasic membrane (Nafion® 212). Several surface characterization techniques were used to verify the engineered membrane's surface after heat treatment, including contact angle, multi-mode atomic force microscopy (AFM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). We found that specific heat treatment conditions will lead to the formation of either a hydrophobic or hydrophilic surface layer. The results of this research will guide the design of a new class of PEMFC catalyst layers. Engineered PEMFC catalyst layers are expected to prevent electrode flooding, therefore leading to higher performance and efficiency during high power density operations.