中文摘要：

利用复阻抗谱分析技术考察了复合Li_3PO_4的Li_（0.5）La_（0.5）Ti O_3（LLTO）固体电解质的离子电导率,同时还利用X射线衍射图谱、扫描电镜观测和相对致密度测量等实验手段研究了LLTO电解质中第二相的分散情况。结果发现,加入Li_3PO_4第二相后,尽管复合固体电解质LLTO拥有比较高的致密度,但是Li_3PO_4会导致离子电导率的降低。通过分析LLTO的晶体结构,晶界的微观结构和锂含量,阐明了LLTO离子电导率恶化的原因,往LLTO基质中分散的Li_3PO_4导致的锂含量和微观结构的变化是引起锂离子传导行为改变的主要原因。

英文摘要：

The ionic conductivity of Li_3PO_4 dispersed Li_（0.5）La_（0.5）Ti O_3（LLTO） composite solid electrolyte was examined by complex impedance analysis. The X-ray powder diffraction（XRD）, scanning electron microscope（SEM） observation and relative density measurement were also performed to study the dispersion of the second phase into the LLTO electrolyte. Results indicate that the addition of Li_3PO_4 into LLTO matrix decreases the ionic conductivity, though the composites added by the Li_3PO_4 particles show a high compactness. The reasons for the conductivity deterioration were clarified based on the lattice structure of LLTO,microstructures at the grain boundary regions, and the lithium content. The variation of the lithium content and microstructures in the LLTO matrix dispersed by Li_3PO_4 particles are mostly responsible for the behaviors in the ionic conduction.