Ionic conductivities of Na+-ion implanted silico–phosphate glass-ceramics

Glass-ceramics of the phosphorus containing Na5RSi4O12-type (R=rare earth) Na+-superionic conductors (Narpsio-V) in the systems Na2O–Y2O3–P2O5–SiO2 and Na2O–Sm2O3–P2O5–SiO2 were prepared by crystallization of glasses. The optimum conditions for crystallization are discussed with respect to the conduction properties and the preparation of uncracked glass-ceramic Narpsio-V. Large enhancement of electrical conductivity has been observed in the glass-ceramics by ion implantation of Na+ ions at 200 keV with a flux density of 1015 ions/cm2. Upon this implantation the ionic conductivity of the glass-ceramic Na3.9Y0.6P0.3Si2.7O9 and Na3.9Sm0.6P0.3Si2.7O9 at 300°C is drastically increased from 2.01×10−2 to 5.86×10−2 S/cm and from 2.38×10−2 to 7.15×10−2 S/cm, respectively.