EFFECTS OF GAS FLOW RATE AND CATALYST LOADING ON POLYMER ELECTROLYTE MEMBRANE (PEM) FUEL CELL PERFORMANCE AND DEGRADATION

摘要

In this paper, the effects of gas flow rates, and catalyst loading on polymer electrolyte membrane fuel cell (PEMFC) performance was investigated using a 50cm~2 active area fuel cell fixture with serpentine flow field channels machined into poco graphite blocks. Membrane Electrode Assemblies (MEAs) with catalyst and gas flow rates at two levels each (0.5mg/cm~2, lmg/cm~2; 0.3L/min, 0.5L/min respectively) were tested at 60°C without humidification. The cell performance was analyzed by taking AC Impedance, TAFEL plot, open circuit voltage, and area specific resistance measurements. It was observed that MEAs with lower gas flow rate had lesser cell resistance compared to MEAs with a higher gas flow rate. TAFEL plot shows the highest exchange current density value of -2.05 mAcm~2 for MEA with 0.5mg/cm~2 catalyst loading operated at reactant gas flow rate of 0.3L/min signifying it had the least activation loss and fastest reaction rate. Open circuit voltage curve shows a higher output voltage and lesser voltage decay rate for MEAs tested at higher gas flow rates.