A model for mixed potential in direct methanol fuel cell cathode and a novel cell design

Abstract

A model for performance of the cathode side of a direct methanol fuel cell at small currents is developed. In our recent model [13], a direct catalytic methanol–oxygen reaction on the cathode side was assumed. In this work, we assume an electrochemical mechanism of methanol oxidation reaction (MOR) in the cathode. The model predicts 600mV-potential loss at OCV, which is close to the experimental data. This result gives confidence on the electrochemical mechanism of MOR in the cathode and it suggests a novel three-electrode DMFC design. The third auxiliary electrode is inserted between the anode and the cathode, and the carbon phase of this electrode is connected to the cathode through a small resistor. The auxiliary electrode is expected to effectively convert the flux of methanol in the membrane into the useful current.