放电电流密度对DMFC交流阻抗的影响  

Effect of discharge current density on alternating current impedance of DMFC

作　　者：刘桂成[1,2] 田哲[2] 王一拓[2] 王新东[1,2] 

机构地区：[1]北京科技大学高效钢铁冶金国家重点实验室,北京100083 [2]北京科技大学物理化学系,北京100083

出　　处：《电池》2012年第4期179-181,共3页Battery Bimonthly

基　　金：国家863项目(2006AA03Z224;2007AA05Z150);国家自然科学基金项目(50528404)

摘　　要：测试了膜电极组件(MEA)在不同工作电流密度(J)下的交流阻抗谱,并用等效电路L1R1(CR2)[QR3(L2R4)]进行拟合。内阻变化最平缓,先减小,后略微增大,变化幅度小于初始值的10%;阴极法拉第阻抗随着电流密度的增大而减小,当J>1.00 A/cm2时,产生的水膜导致三相界面减少后,该阻抗又增大;阳极反应的法拉第阻抗变化最显著,随着电流密度的增大而骤降,证明阳极反应阻抗取决于过电势;过电势不断增大,放电电流增加,导致催化剂表面的吸附物减少,使得阴极双电层电容特性不断增大,体现阳极反应中间物电催化性能的法拉第阻抗和弛豫现象的电感均降低。Alternating current（AC） impedance spectroscopy of membrane electrode assembly （MEA） under different discharge current densities（J） was tested and fitted by the equivalent circuit L1 R1 （CR2）[ QR3 （L2R4）]. The change of internal resistance was the gentlest, decreased firstly and then increased thinly, the change range was less than 10% of the initial value. The cathodic faradaic impedance decreased with the increasing of current density, when J 〉 1.00 A/cm2 and water film was formed,leading the decrease of three phase interface, the impedance was increased. The change of anodic faradaic impedance was most pronounced, de- creased suddenly with the increase of current density,proved that anodie reaction impedance was determined by overpotential. The overpotential increased constantly, the discharge current increased, leading the decrease of adsorbates on the surface of catalyst, making the cathodic double layer capacitor characteristic increased constantly, both faradaie impedance which characterized electro- catalysis performance of intermediates at anodic reaction and inductance which characterized relaxation phenomenon were reduced.

关 键 词：直接甲醇燃料电池 膜电极组件(MEA) 电流密度 交流阻抗 

分 类 号：TM911.46[电气工程—电力电子与电力传动]