Enhanced electrochemical activity of hybrid composite membranes and their proton conductivity Available to Purchase

This study presents a new type of proton-conducting membrane with good structural and electrochemical properties when used as an electrolyte for low-temperature proton-exchange membrane fuel cells. The cross-linking agents, glutaraldehyde and poly(vinyl alcohol), were reacted with tetraethyl orthosilicate and 3-glycidyloxypropyltrimethoxysilane. The obtained membranes demonstrated large proton conductivity, in the order of 10⁻² S/cm at -20 to 140°C and a relative humidity of 50%. The fuel cell performance evaluation was performed at 70°C, and a maximum current density of ~401 mA/cm² was obtained at a cell voltage of 0·6 V. The cell stability was constant during the measurement. The swelling ratio was calculated in dry and wet conditions; it was determined that the membrane had a significant swelling capability. Moreover, the thermal, mechanical and electrochemical stabilities were good. The structural characterization of the composites was investigated using various techniques such as X-ray diffraction, Fourier transform infrared spectroscopy, thermogravimetry analysis and impedance measurements.