Electrical and Dielectric Characterization of Na<sub>0.5</sub>Li<sub>0.5</sub>Zr<sub>2</sub>(PO<sub>4</sub>)<sub>3</sub>

Abstract

Na 0.5 Li 0.5 Zr 2 (PO 4) 3 has been synthesized by solid state reaction and characterized by thermogravimetry/ differential thermal analyses (TGA/DTA) in the temperature range 300-1573 K. X-ray diffraction measurements have been carried out to determine the phase of the composition and scanning electron microscopy (SEM) for microstructure evaluation. Impedance spectroscopy at different temperatures (310-600 K) and frequencies (300 kHz-1 GHz) have been carried out and the dielectric relaxation behaviour was determined under the same conditions. A dc conductivity maximum value of 0.25 S/m at 580 K was observed. However, the mixed alkali effect was not observed. The material exhibited relaxation behaviour with a peak in the dielectric permitivity '  at 469 K. There were no structural transformations observed.

Equivalent circuit models and analysis of impedance spectra of solid electrolyte Na0.25Li0.75Zr2(PO4)3

“…Thus the capacitance of the bulk is almost independent of temperature and the slight increment observed is due to ion migration. There are no peaks observable either, resulting in non Debye behaviour which is in contrast to our earlier results [27]. It is possible that the ratios of the ions in this composition may be responsible for the absence of relaxation behaviour.…”

“…We have investigated the synthesis [26] and the electrical and dielectric permitivity of Na 0.25 Li 0.75 Zr 2 (PO 4 ) 3 mixed ionic conductor . Our earlier investigations based on impedance spectra, dielectric and conductivity analysis revealed a Debye-like character, and a relaxation in the temperature dependence of the permitivity at low frequencies with peaks at ~ 469 K [27]. In the current work we analyze the electrical and dielectric properties of the compound based on equivalent circuit analyses theoretically, using composite electric circuit in complex non linear least squares and generic battery model fitting procedures and determine the mechanisms involved in order to evaluate its suitability for application as solid electrolyte.…”

“…The sample was heated at temperatures from 573 to 1523 K successively, using standard solid state reaction method. Full details of experimental procedure have been described in our earlier works [26,27]. Briefly however, X-ray diffraction (XRD) measurements were carried out using a precision mini XRD diffractometer MD-10, Version 2.0.4 by Radicon Ltd in the 2θ range 16-70 o at a working power of 25 kV, using 20 minutes acquisition time and CuKα radiation λ =1.5406 Å at a scan rate of 0.05 o in other to ensure that the compound is single phase.…”