Novel Gas Diffusion Layers with Separate Gas and Water Pathways for Pemfcs

Proton exchange membrane fuel cells (PEMFCs) as one of the low temperature fuel cells have the advantages of high energy conversion efficiency, high energy density, and environmental friendly emission.The water management on the cathode side ofPEMFCs is a main factor for the fuel cell performance, because too little water will lead to dryness of the membrane with huge ohmic loss, while too much water will block the gas channels and result in flooding. Herein, we have designed a novel gas diffusion layer (GDL) with separate gas and water pathways enabled by3D printing of PTFE in the desired locations and patterns fully controlled by a computer. With this engineered GDL the water generated in the catalyst layer can be extracted out through hydrophilic channels and brought away by the flowing air, whereas oxygen can go through the hydrophobic channels and reach the catalytic sites for the cathodic reaction without being blocked by water.This novel concept is demonstrated using different solid loadings of PTFE in slurries for 3D printing of the GDL, followed by construction of the printed GDL with the MEA,bipolar plates, and end plates to form a proton exchange membrane fuel cell stack. The electrochemical performance of the PEMFC with the 3D printed GDL is compared with that of the PEMFC without the 3D printed GDL under various gas flow rates and humidity conditions. These results will be discussed in this presentation.