Sulfonated PEI membrane with GPTMS-TiO2 as a filler for potential direct methanol fuel cell (DMFC) applications

This study addresses the effect of 3-Glycidyloxy propyl trimethoxy silane (GPTMS)-modified titanium dioxide (TiO2) which composited sulfonated polyetherimide (SPEI) as a proton exchanger on direct methanol fuel cell (DMFC). The membrane fabrication was mainly based on phase-inversion method after GPTMS-TiO2 and SPEI were prepared separately. Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), scanning electronic microscopy (SEM), ion exchange capacity (IEC), proton conductivity, water uptake, methanol permeability, and mechanical properties were utilized to characterize and measure their physical and thermal stability. As the result, high water uptake and IEC performance were achieved using the fabricated membrane. Lower methanol permeability was observed compared to Nafion 117 membranes. The membrane performance showed improvement using 20 wt% SPEI and 5wt% TiO2-5 wt% GPTMS with an optimum result of 3 times lower in terms of methanol uptake and methanol permeability with proton conductivity of 21 mS.cm-1 than the remaining membranes and Nafion. Thus, the obtained results of SPEI/TiO2-GPTMS can be promoted as a novel polymeric membrane for DMFC.