Effect of Sr^2＋ on Properties of Li0.2375＋xLa0.5875-xSrxTiO3-LaPO4 System

Li0.2375+xLa0.5875-xSrxTiO3-LaPO4 fast ionic conductor was synthesized by high temperature solid state reaction.A.C.impedance measurements show that the system has higher conductivity in low doping content of Sr2+,but the conductivity goes down from 5.78×10-5 to 3.11×10-7 S*cm-1 with increasing the content of Sr2+.The activation energy is about 20 kJ*mol-1 in the temperature range of 25～400 ℃.X-ray powder diffraction shows that the doping Sr2+ would not affect the structure of compositions in the system.The main phase is Li0.2375+xLa0.5875-xSrxTiO3 perovskite solid solution,LaPO4 as a second phase can also be found.With increasing the content of Sr2+(x>0.05),another phase SrTiO3 appears.IR measurement also indicates that the structure of compositions in the system would not be affected by Sr2+ doping.The decomposition voltage of Li0.2375+xLa0.5875-xSrxTiO3-LaPO4 remain unchanged(1.5 V).