LiSn1.6Ti0.4(PO4) ceramic powder was synthesized via solid state reaction and investigated for electrical and dielectric properties for use as solid electrolyte. X-ray diffraction shows that it has rhombohedral R3 ̅c NASICON-type structure with unreacted phase of SnO2. Impedance study in the temperature range 300 to 740 K and frequency range 300 kHz-3 GHz were carried out together with dielectric permittivity studies under the same conditions. The determined bulk and grain boundary conductivities are 1.39 x 10-3 S/cm and 3.39 x 10-4 S/cm at 740 K, respectively, while their corresponding room temperature conductivities are 6.31 x 10-6 S/cm and 1.72 x 10-6 S/cm, respectively. Activation energies determined from Arrhenius plot are 0.67 eV and 0.78 eV for bulk and grain boundary, respectively. The determined dielectric constant ε^' has a value of 40 at 303 K and reached a maximum of 1790 at 740 K, which is high compared to most reported values for NASICON and indicate that LiSn1.6Ti0.4(PO4) could be a promising candidate for application as solid electrolyte at elevated temperatures

Abstract

LiSn1.6Ti0.4(PO4) ceramic powder was synthesized via solid state reaction and investigated for electrical and dielectric properties for use as solid electrolyte. X-ray diffraction shows that it has rhombohedral R3 ̅c NASICON-type structure with unreacted phase of SnO2. Impedance study in the temperature range 300 to 740 K and frequency range 300 kHz-3 GHz were carried out together with dielectric permittivity studies under the same conditions. The determined bulk and grain boundary conductivities are 1.39 x 10-3 S/cm and 3.39 x 10-4 S/cm at 740 K, respectively, while their corresponding room temperature conductivities are 6.31 x 10-6 S/cm and 1.72 x 10-6 S/cm, respectively. Activation energies determined from Arrhenius plot are 0.67 eV and 0.78 eV for bulk and grain boundary, respectively. The determined dielectric constant ε^' has a value of 40 at 303 K and reached a maximum of 1790 at 740 K, which is high compared to most reported values for NASICON and indicate that LiSn1.6Ti0.4(PO4) could be a promising candidate for application as solid electrolyte at elevated temperatures.