Pt Degradation Characteristics of Cross-Temperature PEM Fuel Cell Considering the Carbon Corrosion Effect under Dynamic Loading Conditions

With the increase in the power density of proton exchange membrane fuel cells, the requirements for cell heat dissipation are also increasing. Raising the cell operating temperature to the boiling point temperature range (100–120 °C) can increase the temperature difference between the cells and the external environment, which is an effective method to enhance the cell heat dissipation capacity. However, a high temperature promotes the formation of peroxides on the surface of Pt catalysts and carbon supports, which react with each other to release carbon dioxide, causing carbon support corrosion. Carbon corrosion can exacerbate Pt degradation and reduce the fuel cell life. Therefore, taking into account the characteristics of a cross-temperature (C-T) fuel cell operating at high temperature, a Pt degradation model considering the carbon corrosion effect under dynamic loading conditions is constructed. In this model, the coupling effects of electrochemical dissolution/redeposition, Pt precipitation in the membrane, and Pt particle detachment/agglomeration are simultaneously considered, which can accurately describe the Pt degradation processes of normal-temperature (N-T) and C-T fuel cells under dynamic loading conditions. The characteristic parameters of Pt catalysts after degradation can also be obtained. Based on this model, this study found that the Pt degradation processes in N-T and C-T fuel cells are dominated by dissolution/redeposition and detachment/agglomeration, respectively. In addition, through the analysis of carbon corrosion dynamics, it was found that carbon corrosion mainly occurs during the rapid voltage change period, and the carbon corrosion rate is inversely proportional to the voltage change rate and the Pt particle size on the surface of the carbon support.