Effects of operating temperature on the carbon corrosion in a proton exchange membrane fuel cell under high current density

Abstract

• Temperature has the opposite effect on the carbon corrosion kinetic mechanism and water flooding. • Temperature and flooding were the main reasons for carbon corrosion in the upper and bottom areas. • Water management was very important at the outlet of PEMFC operated at high current density. Carbon corrosion in catalysts is one of the main limitations of proton exchange membrane fuel cell (PEMFC) lifetime. Water flooding can accelerate the carbon corrosion rate in PEMFCs, especially at high current densities. Increasing the operation temperature can effectively mitigate water flooding and improve the water management performance of PEMFCs. However, elevated temperatures also increase the carbon corrosion reaction kinetics, accelerating the degradation of PEMFCs lifetime. To study the effects of temperature on carbon corrosion at high current densities, PEMFCs operating for 100 h at 65 °C and 90 °C under 1600 mA·cm −2 were investigated. The results showed that the electrochemical active surface area (ECSA) of the cathode catalyst layer decreased by 9.16% and 13.92% at 65 °C and 90 °C, respectively. The reduction rate of the catalyst layer in the nonflooding area increased as the operating temperature increased. However, the reduction rate decreased by 69.82% and 54.04% at 65 °C and 90 °C, respectively, at the outlet of the PEMFC. Therefore, water flooding is the key issue causing lifetime degradation, and water management is essential for PEMFCs that operate at high current densities, especially at the outlet of PEMFCs.