Performance degradation studies on PBI/H3PO4 high temperature PEMFC and one-dimensional numerical analysis

Five hundred hours continuous aging test at constant discharge current (640 mA cm−2) was performed on PBI/H3PO4 high temperature PEMFC unit cell, electrochemical techniques-linear sweep voltammetry (LSV) and AC impedance measurement were used to investigate the changes of electrochemical surface area (ESA) and high frequency resistance (internal resistance) with time. Initial experimental results showed that during 500 h continuous aging test the main reason for cell performance degradation is the decrease of ESA caused by sintering. In addition, a one-dimensional mathematical model was constructed, the concentration distributions of cathode reactant gases (O2 and gaseous H2O) were calculated and polarization curves recorded during aging test were simulated based on the model, the simulated polarization curves compare well with the experimental results.