A model of a partially flooded anode-backing layer (ABL) in a direct methanol fuel cell (DMFC)

Abstract

Direct methanol fuel cells (DMFCs) generate electrical energy from an electro-chemical reaction between methanol and oxygen in the presence of a platinum containing electro-catalyst. They normally have the following components: (a) the anode gas channel, (b) the anode backing layer (that distributes liquid methanol and water from the anode gas channel to the anode catalyst layer), (c) the anode catalyst layer (that performs the reaction, CH 3OH + 2H2O = CO2 + 6H+ + 6 e -), (d) the electrolyte layer (that transports H+ from the anode catalyst layer to the cathode catalyst layer), (e) the cathode catalyst layer (that performs the reaction 32 O2 + 6H+ + 6 e- = 3H 2O, (f) the cathode backing layer (that distributes oxygen from the cathode gas channel to the cathode catalyst layer and transports water formed in the cathode catalyst layer to the cathode gas channel), and (g) the cathode gas channel. The direct methanol fuel cell being modeled in this project is being developed primarily for low power applications (lap-tops, PDA's) and to a lesser extent for transportation applications (automobiles, fork-lifts). A major problem in DMFC's is methanol crossover from the anode to the cathode without any electrochemical reaction. (Abstract shortened by UMI.)