Direct use of alcohols and sodium borohydride as fuel in an alkaline fuel cell

The performance of an alkaline fuel cell (AFC) was studied at different electrolyte concentrations and temperatures for the direct feeding of methanol, ethanol and sodium borohydride as fuels. Potassium hydroxide is used as the electrolyte in the alkaline fuel cell. The anode was prepared by using Pt black, carbon paper and Nation dispersion. Nickel mesh was used as the current collector. A standard cathode made of manganese dioxide/carbon paper/Ni-mesh/Teflon dispersion (Electro-Chem-Technic, UK) was used for testing the fuel cell performance. The experimental results showed that the current density increases with increase in KOH concentration. Maximum current densities of 300, 270 and 360 A m(-2) were obtained for methanol, ethanol and sodium borohydride as fuel respectively with 3 M KOH electrolyte at 25 degrees C. The cell performance decreases with further increase in the KOH concentration. The current density of the alkaline fuel cell increases with increase in temperature for all the three fuels. The increase in current density with temperature is not as high as expected for sodium borohydride. These results are explained based on an electrochemical phenomenon and different associated losses. (c) 2005 Elsevier B.V All rights reserved.