Optimizing Ionomer Distribution in Anode Catalyst Layer for Stable Proton Exchange Membrane Water Electrolysis

Han Liu; Xinhui Wang; Kejie Lao; Linrui Wen; Meiquan Huang; Jiawei Liu; Tian Hu; Bo Hu; Shunji Xie; Shuirong Li; Xiaoliang Fang; Nanfeng Zheng; Hua Bing Tao

doi:10.1002/adma.202402780

Optimizing Ionomer Distribution in Anode Catalyst Layer for Stable Proton Exchange Membrane Water Electrolysis

Adv Mater. 2024 Apr 25:e2402780. doi: 10.1002/adma.202402780. Online ahead of print.

Authors

Han Liu^{1

2}, Xinhui Wang^{1

2}, Kejie Lao^{1

2}, Linrui Wen², Meiquan Huang^{1

2}, Jiawei Liu^{1

2}, Tian Hu^{1

2}, Bo Hu², Shunji Xie^{1

2}, Shuirong Li³, Xiaoliang Fang^{1

3}, Nanfeng Zheng^{1

2}, Hua Bing Tao^{1

2}

Affiliations

¹ State Key Laboratory for Physical Chemistry of Solid Surfaces, Collaborative Innovation Center of Chemistry for Energy Materials, and College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, China.
² Innovation Laboratory for Sciences and Technologies of Energy Materials of Fujian Province (IKKEM), Xiamen, 361005, China.
³ College of Energy, Xiamen University, Xiamen, 361005, China.

PMID: 38661112
DOI: 10.1002/adma.202402780

Abstract

The high cost of proton exchange membrane water electrolysis (PEMWE) originates from the usage of precious materials, insufficient efficiency, and lifetime. In this work, an important degradation mechanism of PEMWE caused by dynamics of ionomers over time in anode catalyst layer (ACL), which is a purely mechanical degradation of microstructure, is identified. Contrary to conventional understanding that the microstructure of ACL is static, the micropores are inclined to be occupied by ionomers due to the localized swelling/creep/migration, especially near the ACL/PTL (porous transport layer) interface, where they form transport channels of reactant/product couples. Consequently, the ACL with increased ionomers at PTL/ACL interface exhibit rapid and continuous degradation. In addition, a close correlation between the microstructure of ACL and the catalyst ink is discovered. Specifically, if more ionomers migrate to the top layer of the ink, more ionomers accumulate at the ACL/PEM interface, leaving fewer ionomers at the ACL/PTL interface. Therefore, the ionomer distribution in ACL is successfully optimized, which exhibits reduced ionomers at the ACL/PTL interface and enriches ionomers at the ACL/PEM interface, reducing the decay rate by a factor of three when operated at 2.0 A cm^-2 and 80 °C. The findings provide a general way to achieve low-cost hydrogen production.

Keywords: PEM water electrolysis; anode catalyst layer; catalyst ink; gradient ionomer distribution; interface.

Abstract

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