Influence of the sintering of electrocatalysts and decrease of proton conductivity on the current-voltage performance in the high-temperature proton exchange membrane fuel cells (HT-PEMFC)

The influence of the sintering of electrocatalysts and decrease of the proton conductivity on the current-voltage performance in the HT-PEMFC was theoretically evaluated under the non-humid conditions at 150 °C, 170 °C and 190 °C. Decreasing rate of the proton conductivity was evaluated based on the tortuosity of the proton pass. The more the phosphoric acid was evaporated with a rise in temperature, the proton path found to become more tortuous and the proton conductivity was accordingly estimated to be decreased. A theoretical breakdown of the voltage drops indicated that the sintering of the electrocatalyst influenced on the voltage drop in earlier several hundreds of hours. The following voltage drop in the latter stage was caused mainly due to the decrease in the proton conductivity.