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

Nasicon-type Li 1+x Al x Ge 2-x (PO 4 ) 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 Li 1.4 Al 0.4 Ge 1.6 (PO 4 ) 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 LiFePO 4 /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 Li 1.4 Al 0.4 Ge 1.6 (PO 4 ) 3 electrolyte is a potential electrolyte for all solid state lithium-ion battery.