伏安曲线与交流阻抗联合解析燃料电池阻力

Investigation of polarization resistance of fuel cells by combining current-voltage curves with EIS curves

探讨了采用伏安曲线拟合法和交流阻抗谱拟合法得到的燃料电池电化学极化电阻、欧姆极化电阻和浓差极化电阻之间的关系。研究结果表明,采用这两种方法可得到相近的电化学极化电阻,但欧姆极化电阻和浓差极化电阻的差别比较大。从伏安曲线上得到的欧姆电阻比从交流阻抗谱曲线上得到的欧姆电阻大,高出的部分为电池的接触电阻。从交流阻抗谱曲线上得到的浓差极化电阻只包括了迁移离子在电极内部和表面上的扩散阻力,不包含气体扩散的阻力;从伏安曲线上得到的浓差极化电阻不适合外推至低电流密度和超出实验数据点的高电流密度范围。

The relationship of electrochemical polarization resistance,ohmic polarization resistance and concentration polarization resistance derived from fitting I-V curve and EIS curve was investigated in this paper.The results show that the value of electrochemical polarization resistance derived by the two methods is similar,while the difference of ohmic polarization resistance and concentration polarization resistance with the two methods are very distinct.The difference of ohmic polarization between by fitting results of I-V curve and by fitting EIS curve is the contact resistance.The concentration polarization resistance derived from EIS curve only includes the ion diffusion resistance and excludes the gases diffusion resistance.On the other hand,the concentration polarization resistance derived from I-V curve is not suitable for extrapolating to lower current density and exorbitant current density beyond experimental data.