Optimizing Anode GDL of Polymer Fuel Cells for Improving Performance at Low Humidity.

In order to improve the performance of polymer fuel cells in low-humidity environments. This paper investigates the anode gas diffusion layer (GDL), uses carbon black and polytetrafluoroethylene (PTFE) as conductive and hydrophobic materials, NH4HCO3 as pore-forming agent. Anode GDL with dual MPL structure was prepared by the spraying method, and dual MPL has gradient hydrophobicity and pore-sized structure, which greatly ensures high efficiency in the water transport process. This has been tested for polarization curves, power density, electrochemical impedance, SEM, roughness, water contact angle, resistivity, etc. It was found that when the total thickness of MPL is 80 μ m, the thickness of the first layer of MPL is 20 μ m, and the second layer of MPL is 60 μ m, which can achieve good electrochemical performance. When humidity is 40%, the power density is higher than SGL29BC, and the current density can reach 1700 mA/cm2(Pt = 0.2 mg/cm 2). It is concluded that anode GDL with gradient pore size and gradient hydrophobicity can improve the performance of polymer fuel cells at low humidity (40%), and can enhance the water management ability of cathode GDL. Gradient pore size GDL was prepared by spray coating method. When the Pt loading was 0.2 mg/cm2, the power density could reach 1700 mA/cm2 at low humidity (40%). The results showed that the anode GDL, with gradient pore size and gradient hydrophobicity, could improve the performance of polymer fuel cells at low humidity (40%) and enhance the water management ability of cathode GDL. [ABSTRACT FROM AUTHOR]