Li_2Mo_2O_6多晶材料的结构与电性能的研究

A STUDY ON THE STRUCTURE AND THE ELECTR-ICAL PROPERTIES OF THE POLYCRYSTAL MATER IAL Li_2Mo_2O_6

本文用固相反应烧结制备出Li_2Mo_2O_6多晶材料。经X射线分析、红外光谱和电子顺磁共振谱(EPR)的研究,确定了它的结构是Li_2Mo_2O_6和MoO_1两个晶相组成的烧结体。钼离子以四价状态存在于MoO_2晶相结构中。采用交流阻抗谱分析了晶界与温度变化的相关性。测得了样品的ln(1叶agT)-1/T曲线是由两段直线和一段曲线所组成;总电导率化能σ_(27·C)=1.36×10^(-3)(Ω·cm)^(-1),σ_(115·C)=1.49×10^(-3)(Ω·cm)^(-1),σ_(300·C)=9.71×10^(-3)(Ω·cm)^(-1),σ_(370·C)=2.42×10^(-3)(Ω·cm)^(-1);电导活化能E_1=0.043eV,E_2=0.235eV,E_(平均)=0.76eV。采用维格纳极化电池法测得电子电导率4,σ_(e27·C)=2.240×10^(-5)(Ω·cm)^(-1),σ_(e300·C)=4.476×10^(-3)(Ω·cm)^(-1)。实验证明,室温下材料为固体电解质,300℃附近为良好的离子与电子混合导体。

The polycrystal material Li2Mo2O6 is prepared using solid phase firing method. By X-ray diffraction, IR and ESR spectra, we determined that the polycrystal material is composed of two phases: Li2MoO4 and MoO2. Molybdenum exists in MoO2 crystal phase in the form of Mo4+. The relationship between crystal interface and temperature is analyzed by AC complex impedance spectroscopy. The AC conductivity is measured and it is found that the ln(σT)-l/T curve consists of two straight and one curved segments. The conductivity is σ27℃ = 1.36×10~3(Ω·m)-1 σ115℃= 1.49×10^(-3)(Ω·m)-1, σ300℃ = 9.71×10^(-3)(Ω·m)-1,σ370℃ = 2.42×10-2(Ω·m)-1. The activation energy is E1 = 0.043eV, E2 = 0.235eV, E_(av) = 0.76eV. The electronic conductivity σ_c is measured by Wagner method, G_e27℃ = 2.24×10^(-5) (Ω·m)^(-1), σ_(c300℃)= 4.476×10^(-3)(Ω·m)^(-1). It is proved that the material is a solid electrolyte at room temperature and a mixed conductor at 300℃.