EDTA-甘氨酸法制备SmBaCo_2O_(5+δ)阴极材料及其性能

Synthesis and Properties of SmBaCo_2O_(5+δ) Cathode Material via EDTA-Glycine Process

采用EDTA-甘氨酸法(EGP)合成了中温固体氧化物燃料电池(IT-SOFC)的阴极材料SmBaCo2O5+δ(SBCO).通过热重-差热分析(TG-DTA),X射线衍射(XRD),透射电镜(TEM),扫描电镜(SEM),直流四极法及交流阻抗技术分析材料的性能.结果表明,初始粉体在850°C煅烧5 h形成钙钛矿结构单相.EGP制备的SBCO粉体颗粒细小、分散性好、粒径分布均匀,其与Sm0.2Ce0.8O1.9(SDC)电解质材料具有良好的高温化学相容性.SBCO的电导率在500-800°C时达到668-382 S cm-1.以SDC为电解质,SBCO为阴极制备对称半电池,其界面结合良好,颗粒连接充分,形成好的三相界面,具有高的阴极催化活性,750°C时阴极极化电阻为0.0688Ωcm2,远低于固相法(SSR)的值,活化能(Ea)为122.21 kJ mol-1.

SmBaCo=O5＋δ （SBCO） was synthesized as a cathode material for intermediate temperature solid oxide fuel cells （IT-SOFC） via the EDTA-glycine process. The structure and properties of the material were measured by thermogravimetry-differential thermal analysis （TG-DTA）, X-ray diffractometry （XRD）, transmission electron microscopy （TEM）, scanning electron microscopy （SEM）, four-probe DC method, and AC impedance spectroscopy. The results indicated that a stable perovskite phase was formed after the initial powder was calcined at 850 ℃ for 5 h. The obtained powders revealed fine particles with good dispersion and homogeneous size distribution. SBCO had excellent high temperature chemical compatibility with Sm0.2Oe0,801.9 （SDC） electrolyte. The electrical conductivities of the SBCO reached 668-382 S. cm-1 in the temperature range 500-800 ~C. A symmetric half cell with SDC as electrolyte and SBCO as electrode was characterized by good three-phase interface bonding and high cathode catalytic activity. A polarization resistance of 0.0688 Q. cm2 was achieved at 750 ~C for the SBCO, far below that of SBCO synthesized by solid state reaction method （SSR）, with an activation energy （E,） of 122.21 kJ. mol^-L