Temperature Impact on the Internal Resistance of a Polymer Electrolyte Fuel Cell Considering the Electrochemical Impedance Spectroscopy Diagnosis

A polymer electrolyte fuel cell (PEFC) is an electrochemical device that converts the chemical energy presents in the hydrogen into electricity and heat having as by product only water. The energy conversion process is carried out in a clean and noiseless manner. Depending on the applications, a PEFC works at different operating temperature. In this study, the internal resistance of a PEFC is evaluated by using Electrochemical Impedance Spectroscopy (EIS) at moderate low current density, i.e., 0.5 A/cm2, in the temperature range of 40-80°C. The evaluation is carried out considering frequencies between 3.1kHz and 1Hz. An equivalent Randle circuit is considered as adjusted model and the Nyquist and Bode diagram were obtained to analyze the internal resistance. Results show that the ohmic resistance and charge transport increase when the operating temperature is low, decreasing the cell performance. A voltage drop of 42 mV was obtained for the evaluated temperature sweep. At the same time, it was demonstrated that the double layer capacitance increases at high temperatures, increasing its operating performance