Design, fabrication and testing of a direct methanol fuel cell stack

The present paper reports the results of an experimental work done on a direct methanol fuel cell (DMFC) stack. The two cell DMFC stack of active area 16 cm2 is designed, fabricated and tested. The studies are focused on determining the performance characteristics of two cell DMFC stack at various operating conditions and oxygen flow rates. In order to investigate the effect of various operating parameters on DMFC stack performance, experiments are performed at cell temperatures of 50 °C, 60 °C, 70 °C, 75 °C and 80 °C. The methanol concentration varied from 2 M to 5 M in steps of 1 M and cathode (oxygen) flow rate considered are 100 –300 cc/min in steps of 100 cc/min. The membrane electrode assembly (MEA) used is Nafion 117, by loading a Platinum-Ruthenium (Pt-Ru) catalyst at the anode and Pt-black catalyst at the cathode side. Results revealed that the performance of the DMFC was enhanced by increasing the cell temperature, cathode flow rate and methanol concentration. The present DMFC stack shows a peak power density of 0.1 W/cm2 with a cell voltage of 0.4 V and a current density of 0.25 A/cm2 at methanol concentration of 4 M, temperature of 75 °C and oxygen flow rate of 200 cc/min. Comparison study between the stack and single cell of the same stack with 4 M methanol solution under the operating conditions of 200 cc/min and 70 °C is also carried out in which maximum power density of single cell is obtained as 0.04 W/cm2.