Performance of quaternized poly(vinyl alcohol)-based electrolyte membrane in passive alkaline DEFCs application: RSM optimization approach

Direct ethanol fuel cells (DEFCs) have emerged as potential tools for producing sustainable energy for portable devices due to their high energy density and their safe and nontoxic fuel source. However, the main problem of DEFCs is the sluggish oxidation of ethanol and fuel crossover from the anode side to the cathode side. Nafion membranes are commonly used as the electrolyte membrane in DEFCs, but they have a high production cost and high ethanol permeability. Thus, this work studies the performance of an alternative electrolyte membrane that is based on a quaternized poly(vinyl alcohol) (QPVA) polymer in passive alkaline DEFCs. The composition of the QPVA-based membranes was optimized with potassium hydroxide (KOH) as an ion charge carrier and by the inorganic filler graphene oxide (GO). The membrane properties were influenced by KOH and GO. The effect of these two parameters on the performance of the QPVA-based membranes was investigated for its ion-exchange capacity and ionic conductivity and selectivity using the response surface methodology to optimize the membrane composition. The QPVA-based membranes were characterized by Fourier transform infrared spectroscopy, X-ray diffraction, and field emission scanning electron microscope. The membrane properties were influenced by KOH concentration doping and GO filler loading, which affect the membrane selectivity and, consequently, the overall performance of the passive alkaline DEFCs. Finally, the maximum power density of the passive DEFCs was improved from 5.8 to 11.3 W cm(-2) at 30 degrees C, 13.7 mW cm(-2) at 60 degrees C, and 19.3 mW cm(-2) at 90 degrees C, respectively, in ambient air. (c) 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47526.