Polymer Electrolyte Membranes Based on Sulfoethylcellulose and Poly(vinyl Alcohol) for Direct Methanol Fuel Cells

Abstract

We have investigated the solvent uptake, thermal stability, tensile strength, proton conductivity, and the methanol permeability coefficient (PM) in aqueous methanol solutions for cross-linked sulfoethylcellulose/poly(vinyl alcohol) blend membrane (CL-SEC/PVA) and have investigated its applicability to direct methanol fuel cells (DMFC). CL-SEC/PVA membrane exhibits a proton conductivity of 0.017 S cm-1 at 25 ºC. CL-SEC/PVA membrane also shows low methanol permeability in methanol aqueous solutions. The membrane electrode assembly has been prepared by applying Nafion® as a binder in the catalyst layer. Performance of DMFC was estimated with different methanol concentrations. The open-circuit voltage is decreased with increasing the methanol concentration. CL-SEC/PVA membrane achieves the highest power density of 13mW cm-2 with 5M methanol solution at 25 ºC. The results suggest that CL-SEC/PVA membrane is potentially applicable to polymer electrolyte membranes for DMFC utilizing a high concentration methanol solution as a fuel.