Effects of SiO2 and P2O5 on structural, thermal and conductivity properties of inorganic materials doped with PVDF

Abstract

Poly(vinylidene fluoride) (PVDF) doped hybrid glass membranes were prepared with various concentrations of tetraethoxysilane (TEOS), trimethylphosphate and PVDF. The proton conductivities of composites were measured at room temperature under dry conditions. The significant properties of these membranes were their thermal stability, up to 350 °C, and mechanical stability. These properties are adequate for the usage of the membranes in low and intermediate fuel cells. The objective of this work was to improve the conductivity and stability of a class of hybrid composites through optimization of the inorganic compounds and PVDF. The composites were examined using various analytical techniques: XRD, FTIR, ATR, TGA, DSC, proton conductivity and SEM. The H₂/O₂ fuel cells with the hybrid glass membrane show a maximum current density of about 320 mA cm⁻² under the conditions of 60 and 80 °C with a relative humidity of 100%. The results were discussed and compared with the commercially available membranes for fuel cells.