LaAlO_3基电解质与阳极材料的化学相容性及电化学性能

Chemical Compatibility and Electrochemical Performance between LaAlO_3-Based Electrolyte and Selected Anode Materials

采用甘氨酸-硝酸盐法(GNP)合成La_(0.90)Sr_(0.10)Al_(0.97)Mg_(0.03)O_(3-δ)(LSAM)粉体,成型后经1500℃、5h烧结的样品,900℃时其电导率为1.11×10^(-2)S·cm^(-1).利用X射线衍射(XRD)、扫描电镜/X射线能谱分析(SEM/EDX)和交流阻抗技术等表征手段研究NiO-Ce_(0.9)Gd_(0.1)O_(1.95)(Ni-GDC)、Sr_(0.88)Y_(0.08)TiO_3(SYT)和La_(0.75)Sr_(0.25)Cr_(0.5)Mn_(0.5)O_3(LSCM)三种阳极材料与LSAM电解质的化学相容性.结果表明,SYT和LSCM与LSAM的化学相容性欠佳,SYT中的Sr^(2+)和Ti^(4+)向LSAM晶格的扩散明显,LSCM中的Mn^(3+)和Cr^(3+)向LSAM晶格的扩散显著;而Ni-GDC与LSAM具有良好的化学相容性,在1300℃下两材料间阳离子的相互扩散作用极小.800℃时Ni-GDC的比表面极化电阻(R_(ASP))值为5.12Ω·cm^2.LSAM电解质(厚度为550μm)支撑的Ni-GDC/GDC/LSAM/GDC/LSF(La_(0.75)Sr_(0.25)FeO_3)单电池,在800℃时电池的开路电压为0.925V,最大功率密度为19.5 mW·cm^(-2).

Powders of La0.90Sr0.10Al0.97Mg0.03O3-δ （LSAM） were synthesized by the glycine-nitrate process, and then sintered at 1500 ℃ for 5 h. Impedance spectroscopy at 900 ℃ in air revealed that the conductivity of LSAM was 1.11×10-2 S·cm-1. The chemical compatibility of LSAM with anode materials NiO-Ce0.9Gd0.1O1.95 （Ni-GDC）, Sr0.88Y0.08TiO3 （SYT） and La0.75Sr0.25Cr0.5Mn0.5O3 （LSCM） was characterized by X-ray diffraction, scanning electron microscopy with energy-dispersive X-ray spectroscopy and AC impedance spectroscopy. The results indicated that SYT and LSCM had poor chemical compatibility with LSAM because Sr2＋, Ti4＋, Mn3＋, and Cr3＋ diffused readily into the LSAM lattice. The interdiffusion of cations between LSAM and Ni- GDC at 1300 ℃ was limited, implying excellent chemical compatibility. The electrochemical performance of symmetrical cells of the anode materials was measured under hydrogen atmosphere. The area-specific polarization resistance of Ni-GDC was 5.12Ω·cm2 at 800 ℃. An open-circuit voltage of 0.925 V and a power density of 19.5 mW·cm-2 were obtained at 800 ℃ for a 550 μm thick LSAM electrolyte-supported single cell （Ni-GDC/GDC/LSAM/GDC/La0.75Sr0.25FeO3）.