Motivated by such a challenge, a research team led by Prof. YANG Hui at Shanghai Advanced Research Institute (SARI) of the Chinese Academy of Sciences reported a novel ordered MEA based on anode with 3D membrane/catalytic layer (CL) interface and gradient tapered arrays, which not only greatly increases the electrochemical active area but also decreases the overpotentials of both mass transport and ohmic polarization.
The research results were published in Nano Letters recently.
An overall design of the MEA based on anode with ordered arrays, gradient CL and 3D membrane/CL interface structure was proposed and confirmed by scanning electron microscopy, energy disperse spectroscopy and X-ray photoelectron spectroscopy.
Benefiting from the maximized triple-phase interface, rapid mass transport and gradient CL, such an ordered structure not only greatly increases the electrochemical active area by 4.2 times but also decreases the overpotentials of both mass transport and ohmic polarization by 13.9% and 8.7%, respectively.
This ordered MEA ensures a performance of 1.801 V @ 2 A cm-2 even with Ir loading as low as 0.2 mg cm-2, which is comparable with conventional MEA with Ir loading of 2 mg cm-2. Further, it can operate stably over 300 h under 1 A cm-2.
The study provides a simple but effective strategy for the overall design of nanostructured MEA for high-performance and stable PEMWE with low Ir loading.
Structure and performance of the prepared MEA-GTAs-T1 (Image by SARI)