All sprayed fluorine-free membrane electrode assembly for low-platinum and low-humidity proton exchange membrane fuel cells

• Published in: Journal of materials chemistry. A, Materials for energy and sustainability Materials for energy and sustainability, 2023-04, Vol.11 (16), p.92-98
• Main Authors: Yu, Weisheng, Yang, Xiaoqi, Liang, Xian, Xu, Yan, Shen, Xianhe, Ge, Xiaolin, Wu, Liang, Xu, Tongwen
• Format: Article
• Language: English
• Subjects: Accelerated tests; Catalysts; Durability; Electrochemical impedance spectroscopy; Electrochemistry; Electrodes; Fluorine; Fuel cells; Fuel technology; Humidity; Hydrocarbons; Membranes; Platinum; Production costs; Proton exchange membrane fuel cells; Protons; Relative humidity; Spectroscopy; Spraying; Substrates
• ISSN: 2050-7488; 2050-7496
• DOI: 10.1039/d3ta00603d

Reducing the platinum catalyst loading and humidity dependence of membrane electrode assemblies (MEAs) is highly desirable for commercializing proton exchange membrane fuel cells (PEMFCs). Meanwhile, replacing the perfluorinated sulfonic-acid PEMs with fluorine-free hydrocarbon membranes can reduce manufacturing costs. We present an all spraying (AS) method to fabricate a fluorine-free hydrocarbon-based MEA (AS-MEA). Such an MEA achieves a much higher H 2 /O 2 fuel cell performance than the conventional catalyst-coated substrate MEA (CCS-MEA). The peak power density is 1.6 W cm −2 for the AS-MEA vs. 1.2 W cm −2 for the CCS-MEA with 100% relative humidity (RH) and 0.1/0.1 L per min H 2 /O 2 and 0.1 MPa backpressure gas feeds. More importantly, the performance superiority is particularly prominent at low RH and catalyst loading. The AS-MEA achieves a competitive peak power density of 0.6 W cm −2 at 40% RH with a low Pt loading of 0.1 mg cm −2 , which is more than 3-fold that of the CCS-MEA. Equivalent-circuits-based analyses of electrochemical impedance spectroscopy show that the exceptional performance arises from the tightly integrated PEM-catalyst layer boundary, as confirmed by the cross-sectional morphological investigations. Moreover, the AS-MEA shows appreciable in situ durability during a 100 h accelerated stress test. We propose an all-sprayed fluorine-free membrane electrode assembly for low-platinum and low-humidity proton exchange membrane fuel cell application.