Enhanced MEA Performance for an Intermediate-Temperature Fuel Cell with a KH5(PO4)2-Doped Polybenzimidazole Membrane

This work exhibits an effective approach to enhance the performance of membrane-electrode assembly (MEA) with KH5(PO4)(2)-doped PBI membrane, by adding phosphoric acid (PA) in the catalyst layer (CL). The ohmic resistance and single-cell performance of the MEA, treated with PA, are reduced by similar to 80% and improved by similar to 800%, respectively, compared to that of untreated MEA. Based on the MEA pretreated with PA, the influence of humidity and temperature on the resistance and the single-cell performance are investigated. Under humidified gas conditions, the ohmic resistance of MEA is reduced but the charge transfer resistance is slightly increased. Regarding the effect of temperature, the ohmic resistance of MEA becomes lower as the temperature elevates from 140 to 180 degrees C, but increases at 200 degrees C. The maximum peak power density presents at 180 degrees C and 20% RH with 454 mW cm(-2). The peak power density is favored with temperature increase from 140 to 180 degrees C, but decreases with further increase to 200 degrees C. Moreover, when dry gas conditions are employed, the output performance is unstable, suggesting that humidification is necessary to inhibit degradation for a long-term stability test.

Automated summary

The performance of membrane-electrode assembly (MEA) can be significantly enhanced by adding phosphoric acid in the catalyst layer with KH5 (PO4) (2)-doped PBI membrane. The influence of humidity and temperature on the resistance and the single-cell performance of MEA has been investigated, showing that temperature elevation can improve the peak power density.