Composite cathodes for electrolyte-supported solid oxide fuel cells with thin YbSZ electrolyte

Abstract

Reducing the thickness of the electrolyte is a primary method to obtain the electrolyte-supported solid oxide fuel cells with a high performance at the moderate temperature. The 5YbSZ electrolyte substrate shows the high ionic conductivity and mechanical strength, and the single cells configurations with this electrolyte support have been demonstrated to be excellent alternative for SOFCs. Herein, the 5YbSZ electrolyte substrates with the thickness of 90 μm are prepared by the conventional tape-casting method followed by the multilayer lamination. Then, the 5YbSZ electrolyte supported SOFCs with the SSZ-LSM, 8YSZ-LSM, 5YbSZ-LSM and 8YbSZ-LSM composite cathodes are fabricated at the sintering temperature of 1150 °C, and the microstructures and electrochemical properties of these cells are investigated systematically. The maximum power density (Pmax), ohmic resistance (Rs), polarization resistance (Rp) and degradation rate of the single cell with the 5YbSZ-LSM composite cathode are 0.62 W cm−2, 0.189 Ω cm2, 0.377 Ω cm2 and 0.63%/100 h, respectively. Its overall electrochemical properties are best among the four cells, which can be related to its well skeleton structure of the doped zirconia in the cathode. The results highlight that the 5YbSZ-LSM composite cathode having the efficient morphology and high electrochemical properties is more suitable for the 5YbSZ electrolyte supported single cells.