Fabrication and investigation of polymer-based carbon composite as gas diffusion layer of proton exchange membrane of fuel cells

Abstract

Carbon paper is one of the most important component in polymer electrolyte PEM fuel cells. In this research, we report two methods of manufacturing carbon papers that do not need the steps of carbonization and graphitization are common steps in carbon paper. At first method (mixing method), the short carbon fibers have a random distribution in the composite and in the second method (fabric method), the long carbon fibers are oriented in planar configuration .In order to investigate on the properties, the effect of paper thickness and expanded graphite value have been considered and compared with Toray carbon paper. The characterization is performed by scanning electron microscope, maximum pore size, mean pore size, permeability, electrical conductivity, flexibility, and performance (I-V) curve. The results show that mixing method resulting in a higher electrical conductivity, pore size, and permeability, as well as I-V curve similar to Toray paper. In addition, the cost estimates and flexibility test show that both fabric and mixing methods results in a much lower cost, due to removing the graphitization and carbonization steps, and more flexible samples in comparison to Toray paper.