Zeolite-Nafion Composite Membranes as Proton Conducting Materials for High Temperature Direct Methanol Fuel Cells

摘要

Direct methanol fuel cells have good potentialities for application in transportation, portable power sources and distributed generation of clean energy due to their low environmental impact. The main problems that have hindered the market penetration of these systems are the cost of the polymer electrolyte membrane presently used in these devices, the membrane dehydration at temperatures higher than 100-120°C and the methanol cross-over.A direct methanol fuel cell based on a high temperature proton conducting membrane with suitable conductivity and stability up to 130°-150 °C, with proper thermal and water management would become a viable system for mobile applications. Thus, of particular interest are composite membranes with the filler exhibiting strong affinity towards water molecules [1, 2]. In the present work, composite membranes with Nafion as the ion conducting matrix and Chabazite, Clinoptilolite and Mordenite as zeolite fillers have been prepared. These are natural zeolites of fairly low cost and are stable in aqueous solutions within the pH range from 3 to 12 approximately.