【摘要】 通过对具有不同阴极催化剂CoTETA/C载量的质子交换膜燃料电池(PEMFC)运行于不同状态下的交流阻抗分析,提出其等效电路,对各参数模拟表明,在阴极催化剂载量为2 mg/cm2时,随电池温度升高,欧姆阻抗R1和电荷转移阻抗R2呈下降趋势,提高阴极催化剂的载量能够增加电极催化活性,降低R2,但是由于催化剂层增厚,阴极产生的水难以排出,随着温度的升高电极产生部分水淹,R2反而增大,从而导致电池性能下降。电池温度上升,Nafion含水率升高,质子传递阻抗减小,有利于降低R1。在高放电电位时,R2较大,R2占主导地位;在中等放电电位时,R1和R2共同决定电池内阻;低放电电位时,电池处于急剧的浓差极化状态,气体和水的传质将对电池性能产生重要影响。更多还原

【Abstract】 The electrochemical impedance spectroscopy on different loading of cathode catalyst CoTETA/C in proton exchange membrane fuel cell(PEMFC) at different operation conditions was studied.The proposed equivalent circuit shows that,when the loading of cathode catalyst is 2 mg/cm2,with the rise of the operation temperature,the ohm resistance R1 and charge transfer resistance R2reduce;the larger the cathode catalyst loading,the higher the catalytic activity of electrodes and the lower the charge-transfer resistance impedance R2.However,with the increasing of electrode catalyst layer thickness,the water generated in cathode is difficult to excrete.When the operation temperature rises,the electrode is flooded by water,and R2 increases,which lead to the decline of the battery performance.Improving the design of catalyst layer structure and increasing the displacement in the high current is conducive to anti-flooding and reduce the battery concentration polarization.更多还原