质子交换膜燃料电池膜电极催化层的设计与优化

he effect of the PTFE (polytet rafluoroethylene) content in the cathode catalyst layer on the MEA structure and the performance of the single proton exchange membrane fuel cells (PEMFCs) were studied. SEM technique was used to characterize the microstructure of PEMFC. Electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) were used to on-line characteristic the performance of the PEMFCs with different PTFE contents at cathode catalyst layers. It was found that the addition of PTFE affects the performance of fuel cell significantly based on the discharge characteristics. The fuel cell performance is remarkably improved with the increase in the PTFE content at the cathode catalyst layer up to 10%. However, it decreases with further increase of the PTFE content. It has been proven that addition of suitable amount of PTFE improves the dispersion of catalyst and forms worm-like pores, which favors for the higher utilization of catalysts and increases the active surface area for electro-chemical reaction. The most important role of PTFE is the mass-transfer ability of oxygen and water transportation can be improved by decreasing the mass transfer resistance. So the rate-determining kinetic oxygen reduction process can be enhanced. While, excessive PTFE may cover the surface of catalysts and reduce the pore diameter. It reduces the utilization of the catalyst and consequently lowers the fuel cell performance.