Effect of simultaneous addition of aluminum and chromium on the lithium ionic conductivity of LiGe2(PO4)3 NASICON-type glass–ceramics.

New high lithium ion conductor glass–ceramics with NASICON-type structure (Li 1 + x + y Al x Cr y Ge 2 − x − y (PO 4 ) 3 , x + y = 0.5) were synthesized using melt-quenching method and converted to glass–ceramics through heat treatment. Influence of addition of different concentrations of aluminum and chromium in LiGe 2 (PO 4 ) 3 glass-ceramic was investigated. Substitution of Ge 4 + ions by Al 3 + and Cr 3 + ions induced more Li + ions in A 2 vacant sites and also changed the unit cell parameters and resulted in ionic conductivity improvement of glass–ceramics. The glass–ceramics were characterized by X-ray Diffraction (XRD), Field Emission Scanning Electron Microscopy (FESEM), Energy-Dispersive X-ray spectroscopy (EDX), Differential Scanning Calorimetry (DSC), Complex Impedance Spectroscopy (CIS) and cyclic voltammetry (CV). The highest lithium ion conductivity of 6.65 × 10 − 3 S/cm was obtained for x = 0.4 and y = 0.1 (Li 1.5 Al 0.4 Cr 0.1 Ge 1.5 (PO 4 ) 3 ) crystallized at 850 °C for 8 h with minimum activation energy of 0.292 eV. [ABSTRACT FROM AUTHOR]