Synthesis And Assessment Of CuFe₂O₄ As Cathodes Of Inter-mediated Temperature Solid Oxide Fuel Cells

Solid oxide fuel cells（SOFCs） as the cleanest equipment that turn chemical energy of chemical fuel gas to produce electricity directly. Solid oxide fuel cells maintains advantages of fuel cells and perform well on friendly environment characteristic and high chemical stability, getting increasing attention of researchers all over the world. Comparing with common perovskite cathode, Cu Fe₂O₄ materials in this article have unique thermal expansion properties better than cobalt-base cathode and match well with electrolyte, avoiding stripping from electrolyte at high temperature due to thermal swelling, this characteristic prolongs cell’s service life. What’s more, the process of preparing Cu Fe₂O₄ cathode cost less and is more convenient to promot commercial application value and platform of solid oxide fuel cells.Through analysis of TG, it is primarily determined range of Cu Fe₂O₄ cathode calcination temperature. This paper applies two methods of solid-phase and sol-gel to synthesize precursor to be calcined at different temperatures.respectively. 800°C is the most optimum temperature for calcination by XRD characterization. Afterwards, Cu Fe₂O₄ cathode and SSZ electrolyte chemical compatibility are tested under a pretty high temperature of 1200°C, and there is no new or shifting XRD diffraction peak. In terms of thermal expansion properties, Cu Fe₂O₄ cathode performs better compared to other cobalt base material. Screen printing method is ued to coat cathode evenly on the surface of electrolyte to make symmetrical batteries. This paper studied what influence there will be on catalytic performance after changing sintering temperature. Experiments find that cell electrochemical impedance at 900°C is minimal. Impedance of sol gel method at 800°C is 0.132 Ωcm2, whose electrochemical performance is better than 0.140 Ωcm2 of solid phase method. Meanwhile, electrochemical impedance at 650°C of sol gel method is 2.191 Ω cm2, lower than that of solid phase method 2.430 Ωcm2.In order to enhance electrochemical properties of Cu Fe₂O₄ cathode, this article doped Co element to B site and synthesis Cu Fe_2-x Cox O₄（x=0.05, 0.1, 0.05, 0.1） cathode. In the same situation, the cathode electrochemical properties performs better with the Co increased, although at the expense of the part of the thermal expansion properties. Compared with Cu Fe₂O₄ cathode, impedance of Cu Fe1.85Co0.15O₄ cathode at 800 °C is 0.098 Ωcm2. The reason is that existence of Co improved sintering capability of Cu Fe1.85Co0.15O₄ at low temperature, it even has a 1.194 Ω cm2 performance at 650°C. Besides, this paper makes cell with this cathode and gets a maximum discharge power of 1035.3 m W cm-2.Cu Fe_2-x Cox O₄（x=0, 0.05, 0.1, 0.15） are then used to obtain anode-support monomer battery, maximum discharge power at 800°C is 1128.7 m W cm-2 respectively, which proves that spinel oxides are used to much broader prospects during study on solid oxide fuel cell, especially on cathode material.