Stability of lithium ion conductor NASICON structure glass ceramic in acid and alkaline aqueous solution

The stability of lithium ion conducting glass ceramic Li1.5Al0.5Ge1.5(PO4)3 in different aqueous solutions was analyzed with X-ray diffraction (XRD), scanning electron microscopy (SEM) and impedance analysis methods. The XRD results showed that LAGP glass ceramic decomposed into impurity phase Li3PO4 after being immersed in LiOH alkaline aqueous solution for 6 months. The results of impedance analysis indicated that the conductivity of glass ceramic immersed in 0.1 M LiOH alkaline aqueous solution at room temperature for 6 months obviously decreased. However, no conductivity change was observed for samples that were immersed in 1.0 M LiOH solution and saturated LiCl-HAc-H2O and LiCl-LiOH-H2O solutions. This result clearly indicates that Li1.5Al0.5Ge1.5(PO4)3 glass ceramic has excellent stability in saturated LiCl-HAc-H2O and LiCl-LiOH-H2O solutions, suggesting that it is a promising solid electrolyte and electrode protective layer for practical application in lithium/water battery.