Center for Electrochemical Science and Engineering, Department of Chemical & Biological Engineering, Illinois Institute of Technology, Chicago, Illinois 60616, USA.
Phys Chem Chem Phys. 2013 Sep 28;15(36):14994-5002. doi: 10.1039/c3cp51450a.
The oxygen permeability of perfluorinated and hydrocarbon polymer electrolyte membranes (PEMs; Nafion®, SPEEK and SPSU), which are used as electrolytes and electrode ionomers in polymer electrolyte fuel cells (PEFCs), was estimated using chronoamperometry using a modified fuel cell set-up. A thin, cylindrical microelectrode was embedded into the PEM and used as the working electrode. The PEM was sandwiched between 2 gas diffusion electrodes, one of which was catalyzed and served as the counter and pseudo-reference electrode. Independently, from fuel cell experiments, the oxygen transport resistance arising due to transport through the ionomer film covering the catalyst active sites was estimated at the limiting current and decoupled from the overall mass transport resistance. The in situ oxygen permeability measured at 80 °C and 75% RH of perfluorinated ionomers such as Nafion® (3.85 × 10(12) mol cm(-1) s(-1)) was observed to be an order of magnitude higher than that of hydrocarbon-based PEMs such as SPEEK (0.27 × 10(12) mol cm(-1) s(-1)) and SPSU (0.15 × 10(12) mol cm(-1) s(-1)). The obtained oxygen transport (through ionomer film) resistance values (Nafion® - 1.6 s cm(-1), SPEEK - 2.2 s cm(-1) and SPSU - 3.0 s cm(-1); at 80 °C and 75% RH) correlated well with the measured oxygen permeabilities in these ion-containing polymers.
使用改良的燃料电池装置，通过计时安培法估算了全氟聚合物电解质膜（PEM；Nafion®、SPEEK 和 SPSU）和烃基聚合物电解质膜（PEM；SPEEK 和 SPSU）的氧气渗透率，这些膜用作聚合物电解质燃料电池（PEFCs）中的电解质和电极离聚物。将一个薄的圆柱形微电极嵌入 PEM 中作为工作电极。PEM 被夹在两个气体扩散电极之间，其中一个被催化并用作对电极和伪参比电极。独立于燃料电池实验，通过在极限电流下估计覆盖催化剂活性位点的离聚物膜的氧气传输阻力，并将其与整体质量传输阻力解耦，来估算在 80°C 和 75%RH 下由全氟离子聚合物（例如 Nafion®）引起的氧气传输阻力（3.85×10(12)mol cm(-1) s(-1)）比烃基 PEM（例如 SPEEK（0.27×10(12)mol cm(-1) s(-1)）和 SPSU（0.15×10(12)mol cm(-1) s(-1)））高一个数量级。获得的氧气传输（通过离聚物膜）阻力值（Nafion®-1.6 s cm(-1)、SPEEK-2.2 s cm(-1)和 SPSU-3.0 s cm(-1)；在 80°C 和 75%RH 下）与这些含离子聚合物中的氧气渗透率的测量值密切相关。
