Investigation of degradation mechanisms of a high-temperature polymer-electrolyte-membrane fuel cell stack by electrochemical impedance spectroscopy

▸ A graphical method of analyzing the EIS results of PEM fuel cells is introduced. ▸ The EIS analysis can identify degradation mechanisms of PEM fuel cell stacks. ▸ Loss of electrolytes can increase the H+ transport resistance of cathode electrode. ▸ The ORR charge transfer resistance can be affected by the O2 transport rate. ▸ The transport limiting step of O2 is through the electrolytes in the catalyst layer.