School of Environmental Science and Engineering, Gwangju Institute of Science and Technology, 261 Cheomdan-gwagiro, Buk-gu, Gwangju 500-712, Republic of Korea.
Phys Chem Chem Phys. 2010 Dec 14;12(46):15291-300. doi: 10.1039/c0cp00662a. Epub 2010 Oct 16.
Interfacial resistances between the polymer electrolyte membrane (PEM) and catalyst layer (CL) in membrane-electrode assemblies (MEAs) have yet to be systematically examined in spite of its great importance on the fuel cell performance. In order to investigate ionic transport through the PEM/CL interface, the symmetrical impedance mode (SIM) was employed in which the same type of gas was injected (H(2)/H(2)). In this study, the ionic transport resistance at the interface was controlled by the additionally sprayed outer ionomer on the surface of each CL. Effectiveness of the outer ionomer on ionic transport at the interface was quantitatively explained by the reduced contact, proton hydration, and charge transport resistances in the SIM. To characterize the ionic transport resistance, the concept of total resistance (R(tot)) in the SIM was introduced, representing the overall ohmic loss due to proton transport in an MEA. This concept was successfully supported via an agreement of the interpretation and the linear correlation that was obtained between the admittance (1/R(tot)) and the performance of a fuel cell in the ohmic loss region. This correlation will enable researchers to predict the performance of a fuel cell under the influence of proton transport by examining the R(tot) in the SIM.
尽管聚合物电解质膜（PEM）与催化剂层（CL）之间的界面电阻对燃料电池性能非常重要，但在膜电极组件（MEA）中尚未对其进行系统地研究。为了研究通过 PEM/CL 界面的离子传输，采用了对称阻抗模式（SIM），其中注入了相同类型的气体（H2/H2）。在这项研究中，通过在每个 CL 的表面额外喷涂外部离子聚合物来控制界面处的离子传输电阻。通过减少 SIM 中的接触电阻、质子水合和电荷传输电阻，定量解释了外部离子聚合物对界面处离子传输的有效性。为了表征离子传输电阻，在 SIM 中引入了总电阻（R(tot)）的概念，代表由于质子在 MEA 中的传输而导致的整体欧姆损耗。通过解释的一致性以及在欧姆损耗区域中在导纳（1/R(tot)）和燃料电池性能之间获得的线性相关性，成功地支持了这一概念。这种相关性将使研究人员能够通过在 SIM 中检查 R(tot)，预测质子传输对燃料电池性能的影响。
