Influence of Al2O3 additions on crystallization mechanism and conductivity of Li2O-Ge2O-P2O5 glass-ceramics

The crystallization mechanism and conductivity of lithium aluminum germanium phosphate [LAGP] glass-ceramics fabricated from Li1+xAlxGe2-x(PO4)(3) (x=0.0-0.7) glass system were investigated as a function of Al2O3 additions. A non-isothermal analysis was performed to study the crystallization behavior of LAGP glass-ceramics at various heating rates (5-25K min(-1)) by the Kissinger equation and the Augis-Bennett equation, illustrating volume crystallization for the glass-ceramics. The crystal identification and microstructure in glass-ceramics containing various Al2O3 contents were analyzed by means of XRD and FESEM. The main phase of the glass-ceramics was found to be LiGe2(PO4)(3), with AlPO4 as the impurity phase. Additionally the highest total ionic conductivity (5.8 x 10(-4) S/cm) at room temperature was obtained when x=0.5 for Li1+xAlxGe2-x(PO4)(3) (x=0.0-0.7) glass-ceramics, suggesting that it was a promising electrolyte for practical application in all-solid-state lithium batteries. (C) 2011 Elsevier B.V. All rights reserved.