燃料中CO_2杂质对高温质子交换膜燃料电池性能的影响

Effects of CO_2 Content in Fuel on Performance of the HT-PEM Fuel Cell

目的研究燃料中添加不同浓度的CO2对高温质子交换膜(HT-PEM)燃料电池性能的影响.方法运用燃料电池测试系统对HT-PEM燃料电池的伏安特性和交流阻抗特性进行测试,并采用等效电路分析获得了HT-PEM燃料电池的等效元件,分析了重整燃料H2中CO2含量对HT-PEM燃料电池伏安特性和交流阻抗特性的影响.结果氢燃料中的CO2对HT-PEM燃料电池有一定的毒化作用,主要体现在CO2吸附在催化剂表面,形成了Pt-CO键,降低了电池的开路电压,导致浓差极化加剧.如果通入纯氢气燃料,电池性能可恢复至95.3%水平.结论提高燃料中CO2的含量,燃料电池的法拉第阻抗增大,电池的性能降低;随着温度的升高,电池系统对CO2的容忍度降低;CO2对电池性能的影响可以得到恢复.

The purpose of this paper is to explore effects of different contents of CO2 in fuel on performance of the HT-PEM fuel cell. A fuel cell test system was used to test IV-curves and AC impedances of the HT-PEM fuel cell. The equivalent element of the HT-PEM fuel cell was obtained by equivalent circuit analysis. Effects of CO2 content on characteristics and AC impedances of the HT-PEM fuel cell were analyzed. Results showthat CO2 in hydrogen fuel poisons the HT-PEM FC by reducing fuel cell circuit voltage and intensifying concentration polarization when CO2 is attracted to the surface of catalysts and Pt-CO is built. If pure hydrogen fuel is fed into the fuel cell,the fuel cell performance can be restored to the level of 95. 3%. Conclusions are that the Faraday impedance increases with the rise of CO2 content,which reduces performance of the fuel cell.The endurance of the cell system to CO2 decreases when temperature increases and effects of CO2 on the cell performance can be restored.