Influence of phosphorus sources on lithium ion conducting performance in the system of Li2O–Al2O3–GeO2–P2O5 glass–ceramics

NASICON-type structure lithium ion conductors have been considered as promising solid electrolytes due to its very high Li + -ion conductivity and chemical stability. In this paper, NASICON-type structured Li 1.5 Al 0.5 Ge 1.5 (PO 4 ) 3 (LAGP) glass–ceramics are prepared from crystallization of glass powders, which are obtained by a simple melt-quench method. NH 4 H 2 PO 4 , H 3 PO 4 , P 2 O 5 and H 3 PO 4 &Al(PO 3 ) 3 are used as phosphorus sources, respectively. The obtained LAGP glass–ceramics are systematically characterized with X-ray diffraction, field emission scanning electron microscopy , differential scanning calorimetry and AC impedance spectroscopy . The different impurities are formed depending on the phosphorus sources, which further influence the microstructure. As a result, the lithium ion conductivity is significantly affected by the phosphorus sources. The highest conductivity of 5.21   ×   10 −   4   S·cm −   1 is obtained when H 3 PO 4 is used as the phosphorus source under optimum conditions.