A fundamental issue with micro-tubular Solid Oxide Fuel Cells (SOFCs) is improvement of the mechanical strength of the cell. Fabricated using extrusion and co-firing techniques, the approximately 1.7 mm diameter tubes are composed of NiO-Gd-doped ceria (GDC) as an anode (support tube), GDC as an electrolyte and La0.8Sr0.2Co0.6Fe0.4O3 (LSCF)-GDC as a cathode. The mechanical properties of SOFCs are analyzed through burst testing, c-ring testing, and micro- and nano-indentation testing; the burst test is an especially important parameter because of improved power efficiency at increased fuel pressures. Results from micro- and nano-indentation tests performed on electrolytecoated Ni-GDC anode pellets indicate that the hardness of GDC is comparable or greater than that of YSZ. To develop a trend for the mechanical behavior of micro-tubes in relation to variations in fabrication techniques, several parameters were varied. The standard tubes, used as a baseline for variations had four key design parameters as follows: they were not reduced, contained 40% pore former, were sintered at 1400 °C and had a wall thickness of approximately 0.64 mm. A variation on each of the four parameters was performed. The four variations were 1) to reduce the standard tube, 2) to increase the percent pore former to 60%, 3) to decrease sintering temperature to 1350 °C, and 4) to decrease the wall thickness to approximately 0.56 mm. An average burst strength of 9.6 ± 0.6 MPa was observed for the standard tubes, 14.6 ± 7.0 MPa for the reduced tubes, 5.4 ± 3.2 MPa for the increased pore former, 12.9 ± 4.1 MPa for the decreased sintering temperature and 11.7 ± 2.4 MPa for the thinner tubes.
- Nanotechnology Institute
Mechanical Properties of Micro-Tubular SOFCs
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Roy, BR, Sammes, NM, & Suzuki, T. "Mechanical Properties of Micro-Tubular SOFCs." Proceedings of the ASME 2008 6th International Conference on Fuel Cell Science, Engineering and Technology. ASME 2008 6th International Conference on Fuel Cell Science, Engineering and Technology. Denver, Colorado, USA. June 16–18, 2008. pp. 639-643. ASME. https://doi.org/10.1115/FuelCell2008-65261
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