Research On The Structure And The Performance Of Gas Diffusion Layer For Proton Exchange Membrane Fuel Cells

Membrane electrode assembly (MEA) is one of the key components of proton exchange membrane fuel cells (PEMFCs) which play an important role in the mass transportation and electrochemical reaction. The research and development of MEA with reasonable structure and properties not only determine the performance of PEMFC, but also improve the power density, reduce the cost and accelerate the commercialization of fuel cells.The MEA composes proton exchange membrane catalyst layers (CL) and gas diffusion layers (GDL). In this work, the main focus is on the GDL which has function of water and gas mamgentment. The porous structure of progressive GDL was constructed by adding carbon fiber to the carbon slurry to improve the adhesion. The experiment results show that a peak power density of240mW cm-2was obtained, which is higher than the commercial GDL. On the part of materials, polytetrafluoroethylene (PTFE) was substituted by polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP) and compared with the conventional preparing method of GDL. The preparation of the porous layer slurry was simplified. The intention was to balance the hydrophobicity and the hydrophilicity of the GDL, and hydrophobic support layer was impregnated with isopropyl to increase the affinity of the support layer (SL) and slurry. The experiment results show that a peak power density of260mW cm-2was obtained, which is60mW cm-2higher than the commercial GDL.This article also discussed the effect of the micro porous layer and the binder loading of support layer on fuel cell performance. Physical properties of PVDF-HFP-based SL involving microstructure, hydrophobicity, gas permeability and the PEMFC performance were investigated. The results show that the GDL prepared by this method has an improvement for PEMFC performance under certain condition.