Preparation of novel poly(vinyl alcohol)/SiO2 nanocomposite membranes by a sol-gel process and their application on alkaline DMFCs

Poly(vinyl alcohol)/silica (designated as PVA/SiO2) nanocomposite polymer membranes were prepared by a solution casting method. The characteristic properties of PVA/SiO2 nanocomposite polymer membranes were investigated by thermal gravimetric analysis (TGA), scanning electron microscopy (SEM), atomic force spectroscopy (AFM), micro-Raman spectroscopy and AC impedance method. Alkaline direct methanol fuel cells (DMFCs) comprised of PVA/SiO2 nanocomposite polymer membrane were assembled and examined. Experimental results indicate that alkaline DMFC employing an inexpensive, non-perfluorinated, nanocomposite polymer membrane shows excellent electrochemical performance. The highest peak power density of the DMFC, with 19.57 mW cm(-2) ambient conditions, was achieved using PVA/10 wt.%SiO2 solid polymer electrolyte (SPE), a PtRu anode based on a Ti-screen with a 4 M KOH + 2 M CH3OH solution fuel for a preliminary test. The PVA/SiO2 nanocomposite membrane appears as a viable candidate for future application in an alkaline DMFC. (C) 2011 Elsevier B.V. All rights reserved.