Durability study of gas diffusion backing in proton exchange membrane fuel cells under reverse current conditions.

Proton exchange membrane fuel cells (PEMFCs) can experience reverse current during start-up and shutdown due to local fuel starvation, which also lead to carbon corrosion in the gas diffusion layer (GDL) and significantly reduce the durability of PEMFCs. However, the degeneration of the gas diffusion backing (GDB) is currently unclear. In this work, variety rule of structural and physical parameters are taken as object to investigate the performance degradation of GDB under different carbon corrosion potential. The experimental results indicate that the electrical conductivity experience the most significant decrease in particular at the corrosion potential changes from 0.7 V to 1.4 V. The oxidation of GDB significantly reduces the output power density, leading to a 30.85% decrease in the maximum output power density compared to the uncorroded state. The simulation results suggest that the impact of porosity degradation is relatively insignificant, whereas the electrical conductivity is the most pronounced for the decrease in durability. The findings indicated that the primary determinant of temperature distribution is the heat generated by electrochemical reactions dependent on electrical conductivity. For future technology of corrosion resistance for the GDB, it is necessary to develop carbon corrosion resistant materials and control strategy. • High reverse potentials decrease the fuel cells output performance. • Electrical conductivity has the most critical impact on the durability. • Thermal conductivity degenerate has little effect on temperature distribution. • Electrical conductivity degenerate decrease the oxidation reduction reaction. [ABSTRACT FROM AUTHOR]