The temperature dependence investigation of the frequency dispersion of the electrical properties of lithium-iron spinel doped with La, Y

Abstract

The temperature-frequency dependences of the electrical characteristics of Li2 Fe2,5-x Mex O4 (Ме=La;Y, x=0.01; 0.03; 0.05) spinels synthesized by the «sol-gel» autocombustion technology were obtained by the method of impedance spectroscopy in the temperature range of 298-473 K. Based on their analysis, the main mechanisms of conductivity of these materials in the studied temperature range were identified: hopping and activation, which are competing. The effect of doping lithium-iron spinels with rare-earth metal impurities on these conductivity mechanisms has been investigated. It has been established that the presence of impurities in small concentrations in the synthesized samples significantly decreases their conductivity, mainly due to destruction of the hopping mechanism of electronic conductivity.

Keywords

• impedance spectroscopy
• spinel
• frequency dispersion of electrical conductivity
• activation energy
• arrhenius curves
• hopping mechanism of conductivity