Effects of fluorinated ethylene propylene contents in a novel gas diffusion layer on cell performance of a proton exchange membrane fuel cell

The object of this study is the manufacturing processes and fluorinated ethylene propylene (FEP) contents on the cell performance of the proton exchange membrane fuel cell (PEMFC). These results are useful for optimizing gas diffusion layer (GDL) fabrication processes and the operating conditions of the PEMFC. A traditional GDL with a micro porous layer (MPL) can enhance the water management ability. For the case of the one-stage GDL manufacturing process, carbon paper with an FEP content of 10 wt% has the best fuel cell performance and limiting current density. Besides, in the two-stage GDL fabrication process, when the cathode fuel is air, carbon paper with the same 10 wt% FEP content can delay the occurrence of limiting current density. The types of carbon black have remarkable influences on water management capabilities. It is noted that the XC-72R carbon powder has a relatively appropriate pore volume to have enough water to keep the membrane moist and avoid water flooding. The higher the gas humidification temperature, the faster the electrochemical reaction rate. But when the operating current density is high, it will generate too much water, resulting in water flooding and a decrease in the PEMFC performance. Therefore, when the cathode fuel is air and the inlet humidification temperature is 80°C for the anode and 50°C for the cathode, the limiting current density can be effectively extended to maintain the cell performance.