Novel Gas Diffusion Layer for PEMFC Based on in-Situ Synthesized Carbon Nanofibers/Carbon Paper Composites

Gas diffusion layer (GDL) plays an important role in water diffusion process and as a current collection and support of the membrane electrode for proton exchange membrane fuel cell. In this paper, a novel GDL based on in-situ synthesized carbon nanofibers/carbon paper composite was prepared by a chemical vapor deposition process. Scanning electron microscopy (SEM) and high resolution transmission electron microscope (HRTEM) results display that great mass of carbon nanofibers (CNFs) on carbon paper is considerably uniform and has a high length to diameter ratio. The N₂ adsorption-desorption results reveal that the specific surface area of GDL based on CNFs/carbon paper composite is obviously larger than that of traditional GDL and the mesopores are the dominant pore structure for GDL based on CNFs/carbon paper composite. Raman spectra exhibit that GDL based on CNFs/carbon paper composite performs a high ratio of edge atoms to basal atoms. Polarization experiments prove that MEA based on GDL based on CNFs/carbon paper composite has a less open-circuit voltage loss, a higher current density and a higher power density compared with MEA based on traditional GDL.