锂快离子导体Li1.4Al0.1Mg0.1Ti1.8Si0.1P2.9O12和Li1.8Al0.1Mg0.1Ti1.6Si0.3P2.9O12的合成及导电性能研究

以LiTi2(PO4)3为基,用分析纯原料经高温固相反应(850、900、950℃)制得锂快离子导体材料Li1.4A l0.1Mg0.1Ti1.8Si0.1P2.9O12(以下简称TM1)和Li1.8A l0.1Mg0.3Ti1.6Si0.1P2.9O12(以下简称TM2)。用交流阻抗技术测定了合成物的电导率。反应温度为850、900和950℃合成的TM1在298 K测定的电导率分别为1.05×10-4S/cm,1.11×10-4S/cm,1.31×10-4S/cm;同样条件下合成的TM2的电导率分别为7.41×10-5S/cm,7.81×10-5S/cm,8.11×10-5S/cm。以上数据表明,TM1和TM2的离子电导率随着合成温度的升高而增大。在373、473、573和673 K测定的离子电导率也呈上述趋势。反应温度为950℃的合成物的电导率最高,反应温度为850℃的合成物的离子电导率最低,因此,TM1和TM2的最佳合成温度为950℃。T≥100℃时,TM2的离子电导率比TM1的大。X射线衍射分析结果表明,TM1和TM2在不同的反应温度(850、900、950℃)下均得到空间群为R3c的合成物。

Synthesis and Electric Properties of Lithium Fast Ion Conductors Li1.4Al0.1Mg0.1Ti1.8Si0.1P2.9O12 and Li1.8Al0.1Mg0.1Ti1.6Si0.3P2.9O12

Pure analytic reagents were used to prepare new lithium fast ion conductors Li_(1.4)Al_(0.1)Mg_(0.1)Ti_(1.8)Si_(0.1)P_(2.9)O_(12)(TM1) and Li_(1.8)Al_(0.1)Mg_(0.3)Ti_(1.6)Si_(0.1)P_(2.9)O_(12)(TM2) by high temperature(850,900 and 950 ℃) solid phase reaction.The ionic conductivities of TM1 and TM2 were measured by AC impedance method at 298 K.The conductivities of TM1 synthesized at 850,900 and 950 ℃ are 1.05×10~(-4) S/cm,1.11×10~(-4) S/cm and 1.31×10~(-4) S/cm,and those of TM2 are 7.41×10~(-5) S/cm,7.81×10~(-5) S/cm and 8.11×10~(-5) S/cm,respectively.The data indicate that the conductivities of TM1and TM2 rise with the reaction temperature.The conductivities measured at 373,473,573 and 673 K have the same trend:the conductor synthesized at 950 ℃ has the highest conductivity,while that synthesized at 850 ℃ has the lowest conductivity.The temperature of 950 ℃ is fit for preparing TM1and TM2.At T≥100 ℃,the conductivities of TM2 are bigger than those of TM1.X-ray powder diffraction shows that a Lisicon phase with space group exists in the conductors which were prepared at different high temperatures.