Preparation of Lithium Ion Conductor Glass-Ceramic with High Conductivity for Producing Lithium-Air and all-Solid-State Lithium-Ion Batteries

In this research¡ new lithium ion conductor glass-ceramics with NASICON-type structure (Li1쟬肗Ⴋ졧x-y (PO4)3¡ x=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 LiGe2(PO4)3 glass-ceramic was investigated for ionic conduction improvement. Substitution of Ge4 ions in NASICON structure by Al3 and Cr3 ions induced more Li ions in A2 vacant sites to obtain charge balance and also changed the unit cell parameters. These two factors led to ionic conductivity improvement of synthesized glass-ceramics. The glass-ceramics were characterized and the amorth structures were investigated by X-ray Diffraction (XRD)¡ Field Emission Scanning Electron Microscopy (FESEM)¡ Energy-Dispersive X-ray spectroscopy (EDX)¡ Differential Scanning Calorimetry (DSC) and Complex Impedance Spectroscopy (CIS). The highest lithium ion conductivity of 8.82×10-3 S/cm was obtained for x=0.4 and y=0.1 (Li1.5Al0.4Cr0.1Ge1.5(PO4)3) crystallized at 850 oC for 8 h with minimum activation energy of 0.267 eV.