Synthesis and Preparation of Composite Membranes for Direct Methanol Fuel Cells from Poly(Ether Ketone Quinolines)-Poly(Ether Ether Ketone) Blend and Nafion with Non- and Surface Coated Silicotungstic Acid

Abstract

Poly(ether ketone quinoline) has been synthesized as a composite membrane matrix and has a molecular weight of ~40,000. Composite membranes for direct methanol fuel cells (DMFCs) have been prepared from sulfonated poly(ether ketone quinoline) (SPEEK)-poly(ether ether ketone)(SPEKQ) blend and Nafion with non- and surface coated silicotungstic acid (SiWA). The Nafion/surface coated SiWA composite membranes have excellent potential to be used in DMFCs with a high methanol feed concentration. The surface coated SiWA particles may protect the SiWA particles from "washing out" with water from the feed and suppress methanol crossover. The composite membrane of SPEEK-SPEKQ/SiWA yields a highly porous uniform composite membrane. At a constant feed flow rate, the peak power and current density range increase with respect to the methanol concentration for a Nafion/surface coated SiWA membrane electrode assembly. Peak power of 50mW was achieved for the SPEEK-SPEKQ/SiWA composite membrane.