Developing novel electrodes with ultralow catalyst loading for high-efficiency hydrogen production in proton exchange membrane electrolyzer cells

Technical Report · Wed Oct 19 00:00:00 EDT 2022

DOI:https://doi.org/10.2172/1884815· OSTI ID:1884815

Zhang, Feng-Yuan  ^[1]; Mench, Matthew ^[2]; Cullen, David ^[3]; Meyer, Harry ^[3]; Bender, Guido ^[4]; Ma, Zhiwen ^[4]; Capuano, Christopher ^[5]; Ayers, Kathy ^[5]; Gao, Pu-Xian ^[6]; Li, Kui ^[1]; Yu, Shule ^[1]; Ding, Lei ^[1]; Wang, Weitian ^[1]; Xie, Zhiqiang ^[1]; Aaron, Douglas ^[2]; Roy, Anirban ^[2]; Roenning, Frida ^[2]; Yu, Haoran ^[3]; Wrubel, Jacob ^[4]; Kang, Zhenye ^[4] ; Keane, Alex ^[5]; Cui, Can ^[6]

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1. Univ. of Tennessee Space Inst. (UTSI), Tullahoma, TN (United States)
2. Univ. of Tennessee, Knoxville, TN (United States)
3. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
4. National Renewable Energy Lab. (NREL), Golden, CO (United States)
5. Proton Energy Systems, Inc., Wallingford, CT (United States)
6. Univ. of Connecticut, Storrs, CT (United States)

Hydrogen plays more crucial roles for decarbonizing the planets and meeting the climate challenges because of its high energy density and zero-emission. It can be produced with proton exchange membrane electrolyzer cells (PEMECs) driven by sustainable and renewable energy resources. Although PEMECs have a number of advantages, including high purity production, quick response, and the ability to operate at high pressure facilitating the gas delivering, their performance and cost greatly hinder their commercial-scale applications. To achieve high-efficiency and cost-reduced hydrogen production in PEMECs, we proposed thin engineered liquid/gas diffusion layers (LGDLs) and associated electrodes, i.e., catalyst-coated LGDLs (CCLGDLs), over conventional porous transport layers (PTLs) and catalyst-coated membranes (CCMs). The research approaches in this project are based on material synthesis, in-situ and ex-situ characterizations, component design and treatment, numerical modeling, and cost analysis. The thin and tunable LGDLs (TT-LGDLs) and CCLGDLs were successfully developed with great performance improvement as demonstrated in lab-scale, bench-scale, and system-scale electrolyzer tests. The electrode thickness was reduced from 370 µm to less than 100 µm with simplified fabrication processes. With the catalytically enhanced Ir-based catalyst coating, the as-developed CCLGDLs with a catalyst loading of 0.34 mg_Ir/cm² achieved a cell performance of 1.77 V at 2 A cm^-2, exhibiting the catalyst mass activity enhanced by >20 times with significant catalyst saving over conventional catalyst cell design. In-situ PEMEC characterizations, including the current distribution mapping and high-speed and multiscale visualizations, were conducted for a deeper understanding of mass transport and electrochemical reactions within an electrolyzer with LGDLs and CCLGDLs. A 2D cell model was developed and validated for the enhanced performance on TT-LGDL through reducing ohmic losses due to nonuniform hydration and water transport. Further, the cost analysis results have shown a path to move beyond equivalency and surpass costs associated with the project baseline. In this project, the design and fabrication of TT-LGDLs and CCLGDLs will contribute to the performance enhancement, manufacturing simplification, and cost reduction for PEMECs and other energy conversion devices, thus shortening their pathways towards commercialization. This project also provides a good foundation for furthering the in-situ reaction interface research.

• Research Organization: Univ. of Tennessee, Knoxville, TN (United States); University of Tennessee Space Institute (UTSI), Tullahoma, TN (United States)
• Sponsoring Organization: USDOE Office of Energy Efficiency and Renewable Energy (EERE), Office of Sustainable Transportation. Hydrogen Fuel Cell Technologies Office (HFTO)
• DOE Contract Number: EE0008426
• OSTI ID: 1884815
• Report Number(s): DOE-UTK-8426
• Country of Publication: United States
• Language: English

Related Subjects

08 HYDROGEN
42 ENGINEERING
green hydrogen
electrolysis
proton exchange membrane electrolyzer cell
thin liquid/gas diffusion layer
tunable liquid/gas diffusion layer
TTLGDL
catalyst-coated thin liquid/gas diffusion layer
CCLGDL
integrated electrode
current distribution mapping
high-speed and multiscale visualizations
modeling
machine learning