新型固体氧化物燃料电池阴极材料Ca_(2-x)Sr_xFe_2O_5的电化学性能研究

Electrochemical Properties of New Cathode Materials Ca_(2-x)Sr_xFeO_5 for SOFC

采用固相法合成了固体氧化物燃料电池(SOFC)阴极材料Ca2-xSrxFe2O5(x=0.00,0.05,0.10,0.15,0.20),利用XRD和SEM对其结构和微观形貌进行了表征。结果表明该阴极材料与固体电解质Sm0.8Ce0.2O1.9(SDC)在1000℃烧结时不发生化学反应,且烧结4h后,二者之间可形成良好的接触界面。利用交流阻抗谱技术对阴极材料的电化学性能进行研究,结果显示,阴极上的反应过程主要为电荷的迁移反应,其中Ca1.95Sr0.05Fe2O5电极在空气中700℃下具有最小的极化电阻为0.95Ω.cm2。当测试温度为700℃时,阴极电流密度为74mA.cm-2时,阴极过电位为100mV。

Cathode materials Ca2-xSrxFeO5 for SOFC （solid oxide fuel cell） were prepared by solid state reaction. The structure and morphology of the electrodes were characterized by XRD and SEM, respectively. The results show that no reaction occurred between the electrode and the Sm0.8Ce0.2O1.9 （SDC）electrolyte at 1 000℃ and the electrode formed good contact with the electrolyte after sintered at 1 000℃ for 4 h, AC impedance spectroscopy measurements were used to study the cathode performance. The charge transfer process was found to be the ratelimiting step of the electrode reactions. The Ca2-xSrxFe2O5 cathode gave the polarization resistance （Rp） of 0.95 Ω· cm2 at 700℃ in air. Ca1.95Sr0.05Fe2O5 cathode exhibits the lowest overpotential of about 100 mV at a current density of 74 mA·cm^-2 at 700℃ in air.