Abstract Li1+xTi2-xAlx (PO4)3 (LTAP) x = 0.3, 0.4, 0.5 and 0.7) compounds, prepared at 800 °C by sol-gel, have been studied by X-ray diffraction, Nuclear Magnetic Resonance, Scanning Electron Microscopy and Impedance Spectroscopy. The increment of lithium enhances Li–Li repulsions, favoring the creation of vacancies at the conduction paths intersection (M1 sites), increasing Li mobility along (… M1-M2-M1 …) channels in NASICON phases. The partial elimination of segregated AlPO4, LiAlP2O7 and LiTiPO5 phases increased Ti, Al solubility in NASICON, improving overall conductivity in ceramics prepared at 950 °C. The maximum of “bulk” conductivity was produced in x = 0.4 sample, as a consequence of the creation of M1 vacancies and allocation of Li in M2 cavities with optimal Li/vacancy distribution. The presence of secondary phases increased grain boundary impedance, shifting maximum of overall conductivity to x = 0.3 compound. Obtained results are compared with those reported previously in LTPA samples prepared by the ceramic route.

中文翻译：

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由溶胶-凝胶前驱体制备的 Li1+xTi2-xAlx(PO4)3 (0.3≤ x≤ 0.7) 陶瓷中的锂电导率

摘要 Li1+xTi2-xAlx (PO4)3 (LTAP) x = 0.3, 0.4, 0.5 和 0.7) 化合物，在 800 °C 下通过溶胶-凝胶制备，已通过 X 射线衍射、核磁共振、扫描电子显微镜和阻抗谱。锂的增加增强了锂-锂的排斥力，有利于在传导路径交叉点（M1 位点）处产生空位，增加 NASICON 相中沿（…M1-M2-M1…）通道的锂迁移率。分离的 AlPO4、LiAlP2O7 和 LiTiPO5 相的部分消除增加了 Ti、Al 在 NASICON 中的溶解度，提高了在 950 °C 下制备的陶瓷的整体导电性。在 x = 0.4 的样品中产生了最大的“体”电导率，这是由于 M1 空位的产生和锂在 M2 空位中的分配，具有最佳的锂/空位分布。第二相的存在增加了晶界阻抗，将总电导率的最大值转移到 x = 0.3 化合物。获得的结果与之前在通过陶瓷途径制备的 LTPA 样品中报告的结果进行了比较。