A DIRECT ETHANOL FUEL CELL OPERATING AT INTERMEDIATE TEMPERATURE (100-200OC)

Abstract

Even though investigations regarding DEFC have existed for a few years, there remain problems in terms of efficiency and ethanol crossover. It is considered that the electro-oxidation reaction of ethanol must be complete, involving the release of 12 electrons per ethanol molecule and the breaking of C-C bonds for recovering the maximum energy, that is, it must lead to CO2. The increasing reaction temperature can enhance the cell performance because thermal activation of electro-chemical reaction is pronounced and operating at higher temperature reduces the adsorbed CO species. The obstacle to increasing temperature is the limitation of the most commonly used Nafion® membrane. The dependence on its water content limits the working temperature (< 100 oC). Commercial PBI and Nafion-silica membranes were sandwiched in between electrodes prepared using commercial catalysts, carbon supported platinum and platinum-tin as cathode and anode catalysts respectively. The MEAs were tested at temperature of 100-200oC in the single cell. Both membranes could work at operating temperature of 100-200oC. However based-PFSA membranes still needed wet condition to reach better performance. On the other hand, performance of single cell using PBI membrane at dry system was quite comparable with that of single cell using Nafion-silica membrane.