Comparison of Alkaline Direct Ethanol Fuel Cells With and Without Anion Exchange Membrane

Abstract

The performance of three alkaline direct ethanol fuel cells (ADEFCs) is investigated. All three use identical anode and cathode electrodes, but one uses an anion exchange membrane (AEM) and the other two use nonpermselective porous separators. Ethanol was chosen as the fuel because of its low toxicity, low carbon footage, and market readiness. A direct comparison between ADEFCs with and without AEM is reported. The performance of each cell is studied under different operation conditions of temperature, reactants flow rate, ethanol and potassium hydroxide (KOH) concentrations. The results show that with low cost porous separator, the ADEFC can reach similar power output as those using expensive AEMs. With 1 M ethanol and 1 M KOH aqueous solution, the maximum power densities of 26.04 mW/cm2 and 24.0 mW/cm2 are achieved for the ADEFC employing AEM and porous separator, respectively. This proves the feasibility of replacing AEM with nonpermselective separators. The results suggest that improving the cathode structure in order to provide a better oxygen supply is the key factor to enhance the performance of an AEM free ADEFC.