Oxidation behavior and interface diffusion of porous metal supported SOFCs with all plasma sprayed functional layers in air at 650oC

ABSTRACT

metal supported solid oxide fuel cells (PMS-SOFCs) are regarded as a promising choice for power generation. 430 L steel is a popular choice for SOFC support due to its acceptable electrical performance and stability while offering very-low cost. In this study, we investigate the oxidation kinetics of 430 L porous support and interface between anode and support of plasma sprayed PMS-SOFCs in air at 650°C. The effect of exposure time on the microstructure and phase is studied. The metal support has a mass gain of ~1% after 500 h exposure because a continuous Cr₂O₃ scale formed. The element diffusion across the interface of anode and support is characterized. Thin and continuous scales are found at the interface and hinder the diffusion of Cr. The thickness of oxide scale and Cr diffusion distance is less than 1 μm after 500 h oxidation. In general, the oxidation at 650°C is found to be acceptable. Moreover, a decrease of maximum power density from 0.47 to 0.40 W cm⁻² at 650^°C is found after 500 h oxidation, indicating that sacrificing 16% of initial power density could acquire a continuous Cr₂O₃ scale. The increase of ohmic and polarization resistance should be the reason to the cell performance degradation.

KEYWORDS:

• Metal supported
• Solid oxide fuel cells
• Oxidation
• Diffusion
• Long-term stability

Declaration of interests

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Acknowledgments

This work was supported by the National Key Research and Development Program of China (Basic Research Project, Grant No. 2017YFB0306100), the National Natural Science Foundation of China (Grant NO. 91860114), and the National Key Research and Development Program of China (China-USA Intergovernmental Cooperation Project, Grant NO. 2017YFE0105900).