GENG Aoyan ¹, JIAO Xinyi ¹, WANG Xinxin¹, ZHENG Keqing ², LING Yihan ¹, TIAN Yunfeng ¹

(1. School of Materials Science and Physics, China University of Mining and Technology, Xuzhou 221116, Jiangsu, China; 2. School of Low-Carbon Energy and Power Engineering, China University of Mining and Technology, Xuzhou 221116, Jiangsu, China)

Abstract: La_0.8Ca_1.2Fe_0.9Co_0.1O_4−δ(LCFC) perovskite oxides were prepared by using sol-gel method. Symmetrical solid oxide cells LCFC|GDC|YSZ|GDC|LCFC were assembled by using Y_0.15Zr_0.88O_2−δ(YSZ) as the electrolyte, while LCFC was simultaneously used as the fuelelectrode and airelectrode and Gd_0.1Ce_0.9O_2−δ(GDC) as a barrier to prevent the reaction between the electrode material and electrolyte. Phase structure and chemical stability of the LCFC material were studied by using X-ray diffraction method, high temperature electrical conductivity of the material was measured by using the four-probe method, and the thermal expansion coefficient of the material was also characterized. Electrochemical performance and stability of the symmetrical cell in fuel cell mode (SOFC) and electrolytic cell mode (SOEC) were evaluated, while the microstructure of the cell after testing was observed by scanning electron microscope. In SOFC mode, the maximum power density can reach 0.11 W·cm⁻² at 850 ℃ with wet H₂ as fuel and the electrolysis current density of pure CO₂ electrolysis can reach 0.75 A·cm⁻² at 850 ℃ and 2 V. Meanwhile, the cell has strong structural stability. Therefore, LCFC is a promising symmetrical cell electrode material.

Key words: symmetrical solid oxide cells;La_0.8Ca_1.2Fe_0.9Co_0.1O₄; double doping; electrochemical performance; stability