NASICON结构的锂离子导电微晶玻璃结构与电导率

通过对LixAlx-1Ge3-x(PO4)3(x=1.1～1.9)锂离子导电玻璃的差示量热扫描(DSC)数据,结合XRD及其Rietveld精修、FESEM和交流阻抗等测试方法,研究了该系微晶玻璃的物相组成、主晶相晶胞参数变化情况、微观结构形貌、锂离子电导率和电化学窗口等。结果表明:LixAlx-1Ge3-x(PO4)3(x=1.1～1.9)锂离子导电微晶玻璃析出导电主晶相为LiGe2(PO4)3。当x=1.5时,由于导电主晶相LiGe2(PO4)3晶粒充分长大、分布均匀,晶界清晰,LAGP导电微晶玻璃的室温电导率最高(可达5.3×10-4 S.cm-1),电化学窗口为7.2V,可以满足全固态锂离子电池对电解质高室温电导率和宽电化学窗口的应用要求。

Crystal Structure and Ionic Conductivity of the NASICON-Type Lithium Ion Conducting Solid Electrolyte

The Li_{xAlx-1Ge3-x(PO4)3(x=1.1~1.9) solid solutions were prepared as glass ceramics pellets. The title compounds crystallize in the NASICON (Na Super Ionic Conductor), R3c type structure, space group, and the crystal structures were characterized by the Rietveld method with laboratory powder diffraction data. The annealed glasses and glass ceramics were also characterized by DSC, FESEM and AC Impedance techniques. The results indicate that the major phase of the glass ceramics is LiGe2(PO4)3, with AlPO4 and Li4P2O7 as the side-phases for some samples. Additionally, the highest total ionic conductivity (5.3×10^-4 S·cm^-1) at room temperature is obtained when x=1.5 for xAlx-1Ge3-x(PO4)3 glass ceramics, with homogeneous crystals distribution and wide electrochemical window (7.2 V).}