Synthesis of mixed composite membranes based polymer/HPA: Electrochemical performances on low temperature PEMFCs

The aim of this study was to investigate preparation of novel and high proton-conducting membranes and characterization of their properties and performances for proton exchange membrane fuel cells (PEMFCs) operating at low temperatures. A new class of non-fluorinated PVA/PWA/GPTES/MPTMS/P2O5/GA hybrid composite membranes was prepared in a sol–gel method. Swelling was observed at room temperature for all the composites. The behavior of the conductivity in various temperatures and humidity conditions was determined. A maximum conductivity value of 0.025 S/cm was found at a 140 °C and 50% relative humidity conditions. It is suggested that the conductivity strongly depends on the nature of the organic/inorganic components as well as on the acid concentration. X-ray diffraction (XRD) results demonstrated that this membrane had an amorphous phase, and Fourier-transform infrared spectroscopy (FTIR) results confirmed the formation of the composite. Finally, membrane electrode assemblies with a loading of 0.1 mg/cm2 of Pt/C on a prepared electrode produced a current density of 309 mA/cm2 at a voltage of 0.5 V.

► A class of non-fluorinated hybrid composite membrane was synthesized by sol–gel method. The thickness of the membrane was 0.6–1 mm.
► The obtained membranes showed large proton conductivity, in the order of 0.025 S/cm.
► A maximum current density of 309 mA/cm2 was obtained at 80 °C and the relative humidity of 100% RH.