基于La_(0.8)Ca_(1.2)Fe_(0.9)Co_(0.1)O_(4-δ)对称电池的制备与性能研究

Preparation and Performance of Symmetrical Solid Oxide Cell with La_(0.8)Ca_(1.2)Fe_(0.9)Co_(0.1)O_(4-δ) Electrode

以Y_(0.15)Zr_(0.88)O_(2-δ)(YSZ)为电解质,利用溶胶—凝胶法制备了La_(0.8)Ca_(1.2)Fe_(0.9)Co_(0.1)O_(4-δ)(LCFC)钙钛矿材料并同时作为固体氧化物电池的燃料极和空气极,Gd_(0.1)Ce_(0.9)O_(2-δ)(GDC)作为阻挡层防止电极材料与电解质反应,制备得到了对称固体氧化物电池LCFC|GDC|YSZ|GDC|LCFC。采用X射线衍射研究了LCFC材料的物相结构以及化学稳定性,四电极法测量了材料的高温电导率,并测试了材料的热膨胀系数。评估了对称电池在燃料电池模式(SOFC)和电解池模式(SOEC)下的电化学性能与稳定性,并利用扫描电镜观察了电池测试后的微观形貌。实验结果表明,在SOFC模式下,850℃时以湿H_(2)为燃料的最大功率密度可达0.11 W·cm^(-2),电解纯CO_(2)时,在850℃、2V电压下的电解电流密度可达0.75 A·cm^(-2),稳定性测试结果表明,电池具有良好的性能和结构稳定性。结果证明,LCFC材料是一种有发展前景的对称电池电极材料。

La_(0.8)Ca_(1.2)Fe_(0.9)Co_(0.1)O_(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_(0.15)Zr_(0.88)O_(2-δ)(YSZ)as the electrolyte,while LCFC was simultaneously used as the fuelelectrode and airelectrode and Gd_(0.1)Ce_(0.9)O_(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 H_(2) as fuel and the electrolysis current density of pure CO_(2)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.