微波辅助溶胶凝胶法合成La0.8Sr0.2Co0.5Fe0.5O3阴极材料及性能研究

使用一种新的理想方法--微波辅助溶胶凝胶法,在35 min内快速制备了钙钛矿结构的La0.8Sr0.2Co0.5Fe0.5O3(LSCF)纳米材料;以8%Y2O3稳定化的ZrO2(YSZ)为电解质,La0.8Sr0.2Co0.5Fe0.5O3为阴极,铂电极为阳极,制备了LSCF/YSZ/Pt固体氧化物电池.采用X射线粉末衍射(XRD)、傅里叶红外光谱(FT-IR)、扫描电子显微镜(SEM)、BET和电化学阻抗谱(EIS)等技术研究了La0.8Sr0.2Co0.5Fe0.5O3材料的成相过程、粉晶结构、电极/电解质微观相貌和电池电化学性能.结果发现经过1 min的微波辐射,凝胶开始分解,3 min后有钙钛矿相生成,到35 min时形成了完整的钙钛矿晶相,相应粉体的粒径和比表面积分别为22.7 nm和38.9 m2/g;在1094 K,0 mV偏置电压下电极/电解质界面电阻为0.775 Ω·cm2,活化能为2.34 eV.研究发现,偏置电压越大则活化能越低.

Synthesis and Performances of La0.8Sr0.2Co0.5Fe0.5O3 Cathode by Microwave Assisted Sol-Gel Method

Perovskite structured La0.8Sr0.2Co0.5Fe0.5O3(LSCF)cathode materials were prepared by a microwave assisted sol-gel process.The formation and crystalline structure of powders derived from the chelate solution were analyzed by X-Ray diffraction(XRD),Fourier transformation infrared spectroscopy(FT-IR),scanning electron microscopy(SEM)and BET techniques.In addition,the electrochemical performances of LSCF cathode for zirconia-based solid oxide fuel cells were investigated by Electrochemical Impedance Spectroscopy(EIS)on a three electrode cell,where the sample in this study was the LSCF working electrode and two platinum electrode used as counter and reference electrode.The results show that the gel began to decomposed after about 1 min microwave treatment,then transformed into a great quantity of LSCF and a pure LSCF Perovskite single phase when microwave treated for 3 min and 35 min respectively.Typical mean particle diameters and measured at 1094 K without a DC bias.The LSCF/YSZ interracial resistance activation energies is 2.34 eV.The DC bias has a great effect on the interfacial resistance activation energies,as larger DC bias gives rise to lower activation energies.