Ionic conductivity enhancement in LiGe2(PO4)3 solid electrolyte

In order to improve the ionic conductivity of LiGe2(PO4)3 as a solid electrolyte for lithium batteries, we have examined the effects of Al3+ and Y3+ substitution for Ge4+ and of LiOH-H2O addition on the ionic conductivity. The ionic conductivity of LiGe2(PO4)3 is enhanced four orders of magnitude by Al3+ addition, i.e. 1.3 × 10−4 S cm−1 at 23 °C in case of the Li1.4Al0.4Ge1.6(PO4)3. The addition of Y2O3 or lithium salt also enhances the ionic conductivity because of the acceleration of the sintering process by the second phase of Li4P2O7.