Investigating fuel-cell transport limitations using hydrogen limiting current [electronic resource]

• Ngôn ngữ: eng
• Ký hiệu phân loại: 333.79 Energy
• Thông tin xuất bản: Washington, D.C. : Oak Ridge, Tenn. : United States. Dept. of Energy. Office of Energy Efficiency and Renewable Energy ; Distributed by the Office of Scientific and Technical Information, U.S. Dept. of Energy, 2017
• Mô tả vật lý: Size: p. 13960-13969 : , digital, PDF file.
• Bộ sưu tập: Metadata
• ID: 255733
• Chủ đề: 1. 08 hydrogen; 2. 30 direct energy conversion; 3. Catalyst layer; 4. Effective diffusivity; 5. Gas-diffusion layer; 6. Limiting current; 7. Low loading; 8. Resistance

Tóm tắt

Reducing mass-transport losses in polymer-electrolyte fuel cells (PEFCs) is essential to increase their power density and reduce overall stack cost. At the same time, cost also motivates the reduction in expensive precious-metal catalysts, which results in higher local transport losses in the catalyst layers. Here, we use a hydrogen-pump limiting-current setup to explore the gas-phase transport losses through PEFC catalyst layers and various gas-diffusion and microporous layers. It is shown that the effective diffusivity in the gas-diffusion layers is a strong function of liquid saturation. Additionally, it is shown how the catalyst layer unexpectedly contributes significantly to the overall measured transport resistance. This is especially true for low catalyst loadings. It is also shown how the various losses can be separated into different mechanisms including diffusional processes and mass-dependent and independent ones, where the data suggests that a large part of the transport resistance in catalyst layers cannot be attributed to a gas-phase diffusional process. The technique is promising for deconvoluting transport losses in PEFCs.