Enhancing PEMFC performance at high current density by incorporating PTFE emulsion into catalytic layer.

Mass transfer is a critical bottleneck in the development of proton exchange membrane fuel cells (PEMFCs), especially at high current densities. This study aims to enhance the power density, stability, and durability of the PEMFC by modifying the catalyst layer (CL) with polytetrafluoroethylene (PTFE). The influence of varying PTFE contents in CL was assessed through polarization curves, mass transfer resistance (R mt), and oxygen transfer resistance (OTR) tests. The optimal performance was achieved with MEA4 (with 40 % PTFE), demonstrating a power density of 847 mW/cm2 at 1700 mA/cm2, an 8 % increase compared to MEA0 (without PTFE) at 75 °C. The R mt of MEA4 decreased to 0.1148 Ω cm2, a 55 % reduction from MEA0 (0.2522 Ω cm2). A stability test at 1600 mA/cm for 5 h showed MEA4 maintaining a stable voltage at 0.527 V, while the MEA0 exhibited a linear voltage decrease of 0.04 mV/min with significant fluctuations over time. Accelerated stress testing (AST) is conducted under the DOE standard by 2000 voltage cycles with a triangle sweep voltage from 1.0 V to 1.5 V, which revealed that the OTR of the MEA0 increased by 37 % from 0.7198 s/m to 0.9914 s/m, whereas the MEA4 was observed to be increased from 0.74707 s/m to 0.8253 s/m with a rise of 10.5 %. In conclusion, the incorporation of PTFE into the CL enhances oxygen transfer within the CL, thus improving the power density, stability, and durability of PEMFCs at high current density. [Display omitted] • The addition of PTFE to the catalyst layer facilitates the mass transfer of PEMFC. • The mass transfer resistance of MEA4 is 0.1148 Ω cm2, 50 % lower than that of MEA0. • After AST, the OTR of MEA4 increased by 10.2 %, obviously lower than MEA0's 37.8 %. • The power density, stability, and durability of MEA with 40%PTFE were better. [ABSTRACT FROM AUTHOR]