Conventional Catalyst Ink, Catalyst Layer and MEA Preparation

The membrane electrode assembly (MEA) is the heart of proton exchange membrane fuel cells (PEMFCs), including direct methanol fuel cells (DMFCs), and determines both fuel cell performance and durability. The MEA component materials, structure, and fabrication technologies play important roles in performance improvement and optimization. For example, the catalyst layers, where the electrochemical reactions take place, are the most important of the several components in PEMFCs. An MEA contains an anode gas diffusion layer (GDL), an anode catalyst layer (CL), a proton exchange membrane (PEM), a cathode catalyst layer, and a cathode gas diffusion layer. An ideal MEA would allow all active catalyst sites in the catalyst layer to be accessible to the reactant (H

2

or O

2

), protons and electrons, and would facilitate the effective removal of produced water from the CL and GDL. Over the past several decades, great efforts have been made to optimize the catalyst layer and MEA, and many catalyst layer/MEA structures and fabrication methods have been developed. As a result, MEA performance with advanced catalyst layers has been significantly improved by employing different fabrication methods [1–4], changing the catalyst layer structures [5–11], and using different components [5–8].

This chapter will address the preparation methods for catalyst inks, catalyst layers, and MEAs, with a focus on the fabrication processes.