CNR-ITAE Institute, Consiglio Nazionale delle Ricerche, Messina, Italy.
ChemSusChem. 2010 Dec 17;3(12):1390-7. doi: 10.1002/cssc.201000223.
Solid Na-β"-Al₂O₃ electrolyte is prepared by a simple chemical route involving a pseudo-boehmite precursor and thermal treatment. Boehmite powder is used for manufacturing the planar electrolyte with appropriate bulk density after firing at 1500 °C. The structure, morphology, and surface properties of precursor powders and sintered electrolytes are investigated by X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS). As shown by XRD and TEM analyses, nanometer-sized particles are obtained for the boehmite precursor and a pure crystallographic phase is achieved for the sintered electrolyte. SEM analysis of the cross-section indicates good sintering characteristics. XPS shows a higher Na/Al atomic ratio on the surface for the planar electrolyte compared to a commercial tubular electrolyte (0.57 vs. 0.46). Energy-dispersive X-ray microanalysis (EDX) shows an Na/Al ratio in the bulk of 0.16, similar in the two samples. The ionic conductivity of the planar electrolyte is larger than that measured on a commercial tube of sodium-β"-alumina in a wide temperature range. At 350 °C, conductivity values of 0.5 S cm⁻¹ and 0.26 S cm⁻¹ are obtained for the planar electrolyte and the commercial tube, respectively. AC-impedance spectra show smaller grain boundary effects in the planar electrolyte than in the tubular electrolyte. These favorable properties may increase the perspectives for applying planar Na-β"-Al₂O₃ electrolytes in high-temperature batteries.
固体 Na-β"-Al₂O₃ 电解质通过一种简单的化学途径制备，涉及拟薄水铝石前体和热处理。拜耳石粉末用于制造具有适当体密度的平面电解质，在 1500°C 下烧制。通过 X 射线衍射（XRD）、透射电子显微镜（TEM）、扫描电子显微镜（SEM）和 X 射线光电子能谱（XPS）研究了前驱体粉末和烧结电解质的结构、形态和表面性质。XRD 和 TEM 分析表明，拜耳石前驱体得到了纳米尺寸的颗粒，烧结电解质达到了纯晶相。横截面的 SEM 分析表明具有良好的烧结特性。XPS 表明，与商业管状电解质相比，平面电解质的表面 Na/Al 原子比更高（0.57 对 0.46）。能量色散 X 射线微分析（EDX）表明，两个样品的体相 Na/Al 比均为 0.16。在较宽的温度范围内，平面电解质的离子电导率大于商用钠-β"-氧化铝管的电导率。在 350°C 时，平面电解质和商用管的电导率分别为 0.5 S cm⁻¹和 0.26 S cm⁻¹。交流阻抗谱表明，平面电解质的晶界效应小于管状电解质。这些有利的性质可能会增加在高温电池中应用平面 Na-β"-Al₂O₃ 电解质的前景。
