Ordered Membrane Electrode Assembly with Drastically Enhanced Proton and Mass Transport for Proton Exchange Membrane Water Electrolysis.

Tian, Bin; Li, Yali; Liu, Yiyang; Ning, Fandi; Dan, Xiong; Wen, Qinglin; He, Lei; He, Can et al. · Nano Lett · 2023

basic_science · Level V

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Abstract

In this work, an ordered membrane electrode assembly (MEA) based on a cone Nafion array with gradient Nafion distribution, tightly bonded catalytic layer/proton exchange membrane (CL/PEM) interface, and abundant vertical channels has been engineered by an anodic aluminum oxide template and magnetron sputtering method. Benefiting from a highly efficient CL/PEM interface, plentiful proton transfer highways, and rapid oxygen bubble release, this ordered MEA achieves an ultralow Ir loading of 20.0 μg cm<sup>-2</sup> and a high electrochemical active area by 8.7 times compared to traditional MEA with Ir loading of 1.0 mg cm<sup>-2</sup>. It yields a mass activity of 168 000 mA mg<sub>Ir</sub><sup>-1</sup> cm<sup>-2</sup> at 2.0 V, which is superior to most reported PEM electrolyzers. Notably, this ordered MEA maintains excellent durability at a current density of 500 mA cm<sup>-2</sup>. This work opens a simple, cost-effective, and scalable route to design ordered MEAs for proton exchange membrane water electrolysis.