Effect of a fluorocarbon- and hydrocarbon-based hybrid surfactant on the preparation of Nafion/ePTFE-reinforced composite membranes

Proton exchange membrane fuel cells (PEMFCs) offer significant potential in the field of next-generation mobility applications. Incomplete ionomer impregnation in reinforced composite membranes (RCMs) deteriorates the performance and durability of PEMFCs because the proton conductivity of RCMs decreases and the gas permeability increases in a single cell. In this study, the impregnation into RCMs was improved by introducing fluorocarbon and hydrocarbon (CF–CH)-based hybrid surfactants into the ionomer solution. The improved impregnation was confirmed using contact angle and proton conductivity measurements, Fourier transform infrared spectroscopy (FTIR), focused ion beam-scanning electron microscopy (FIB-SEM), and energy dispersive X-ray spectroscopy (EDS). In a single cell, the performance and durability of the RCM with the CF-CH hybrid surfactant were better than those of the RCM impregnated with only the ionomer due to the lower membrane resistance and hydrogen crossover in the former. The RCM with the CF-CH hybrid surfactant exhibited a current density of 1.2 A cm−2 at 0.6 V and peak power density of 740 mW cm−2 in a single cell. Thus, high-performance and durable RCMs of PEMFCs can be efficiently fabricated by introducing the surfactant in an ionomer solution. This can significantly advance the mobility applications of fuel cells.