Degradation Mechanism of Anode‐Supported Solid Oxide Fuel Cell In Planar‐Cell Channel‐Type Setup

Abstract

The degradation mechanism of anode‐supported planar solid oxide fuel cells is investigated in the present work. We fabricate a large‐area (10 cm × 10 cm) cell and carry out a long‐term test with the assembly components. A constant current of ∼0.4 A cm–2 is applied to the cell for ∼3,100 h, and the furnace temperature is controlled in the sequence 750–800–750 °C to investigate the effect of operating temperature and thermal cycling on the degradation rate. Impedance spectra and current–voltage characteristics are measured during the operation in order to trace any increase in Ohmic and non‐Ohmic resistance as a function of time. The degradation rate is rapid during the operation at the higher temperature of ∼800 °C compared to that during the operation at ∼750 °C. Even after cooling down to ∼750 °C, that rate is still accelerated. The main contribution to the cell degradation is from an increase in the Ohmic resistance. Postmaterial analyses indicate that the cathode is delaminated at the electrolyte/cathode interface, which is attributed to the difference in thermal expansion coefficient (TEC). Thus, the present results emphasize the importance of matching the TEC between cell layers, especially under severe operating conditions such as long duration and complex thermal cycling.

Progress in Material Development for Low-Temperature Solid Oxide Fuel Cells: A Review

“…Lowering the cell operating temperature can greatly suppress the material degradation due to thermochemical corrosion and therefore is an effective method to increase cell durability. [82,[86][87][88].…”

“…Some cathode materials have poor matching TEC; for example, Co-based and ferrite-based cathodes cannot be used with the YSZ electrolyte [260]. The TEC difference between the layers can lead to cathode electrochemical degradation and delamination during the harsh operating condition of SOFCs [86]. Therefore, several aspects of cathode materials, as discussed above, should be considered in choosing an appropriate material for each layer.…”

Study on the surface segregation of mixed ionic‐electronic conductor lanthanum‐based perovskite oxide La 1−x Sr x Co 1−y Fe y O 3− δ materials

“…Due to the SOFC deterioration induced by cation surface segregation 27,28 is one of the factors that retard the development of SOFC technology thus a comprehensive review of Sr segregation on MIEC materials particularly lanthanum-based perovskite oxide active TPB loss is indispensable. 29,30 This review aimed to provide more information on the phenomenon of surface Sr segregation occurring on the lanthanum-based perovskite cathode, which is an important factor that contributes to cathode degradation the most.…”

Mechanism of the cathode current collector on cell performance in a solid oxide fuel cell stack

“…For instance, new electrode materials [5][6][7][8] and nanostructures [9][10][11] have been reported, which resulted in a maximum power density ≥ 2.9 W•cm −2 at 650 o C with humidified 3% H 2 as fuel and air as oxidant. On the contrary, the power density of an SOFC stack is generally less than 0.6 Wcm −2 [12][13][14][15], which determined by the contact layer between the cathode and the interconnect [16][17][18][19][20]. Because of the high-temperature oxidation atmosphere at the cathode side, researchers initially attempted to print noble metal slurry on the cathode as a current collector [21][22][23].…”