A Comparative Analysis of Performance Characteristics in Passive and Active Fed DMFC Systems

In this study, the performance of active and passive Direct Methanol Fuel Cells (DMFCs) with different structural configurations was experimentally compared. In addition to the active cell designs commonly used in the DMFC field, a new passive DMFC configuration featuring a single passive reservoir was designed and fabricated. A performance comparison of the two designs was conducted under similar operating parameters. The fundamental difference between the two cell designs is that in the active-fed system, the fuel is continuously delivered to the anode region via a pump, whereas in the passive DMFC, anode feeding is provided through a fuel reservoir that covers the entire active surface. The active area of both designs, constructed with similar components, was set at 25 cm². Tests were conducted for different reactant conditions at a constant methanol concentration of 2 M and a constant fuel temperature of 50 °C. On the cathode side, reactant transport was investigated using similar air flow rates of 1, 1.5, and 2 L/min in both configurations. According to the performance results, a maximum power density of 80.3 mW/cm² was achieved in the active-fed cell design, while this value was measured at 12 mW/cm² in the passive DMFC configuration. The findings were compared with the operating conditions and internal resistances of the designs using Eis measurements. The test results demonstrate that, through optimization approaches, active-fed DMFCs can achieve significantly higher power densities compared to passive designs.