Facile synthesis and performance of NASICON Li1+xAlxGe2-x(PO4)3 electrolytes for all solid state lithium-ion battery

Nasicon-type Li1+xAlxGe2-x(PO4)3 (x = 0–0.5) electrolytes have been prepared via a facile and economic method. All synthetic electrolyte samples show Nasicon structure and good crystallinity. The Al doping content has a great influence on the electrical conductivity of electrolyte. The electrolyte with the composition of Li1.4Al0.4Ge1.6(PO4)3 exhibits a highest electrical conductivity of 2.72 × 10−4 S/cm at room temperature, which is mainly attributable to fewer impurity and dense electrolyte structure. The LiFePO4/Li cell assembled with this electrolyte delivers an initial specific discharge capacity of 127.86 mAh g−1 at a charge/discharge current density of 0.5C at 60 °C, which shows an excellent cycling performance with high discharge capacity of 131.2 mAhg−1 after 150 cycles. These results suggest that the Li1.4Al0.4Ge1.6(PO4)3 electrolyte is a potential electrolyte for all solid state lithium-ion battery.