Dense nanostructured solid electrolyte with high Li-ion conductivity by spark plasma sintering technique

Abstract

Spark plasma sintering (SPS) technique has been attempted to prepare dense lithium ion conductors composed of nanostructured Li 1.4Al 0.4Ti 1.6(PO 4) 3 with the NASICON-type structure. Typical 100% of theoretical density in the pellets was achieved for the sample by SPS at 650 °C, a much lower temperature compared to the solid-state sintering process. The ionic conductivity of 1.12 × 10 −3 S/cm, the highest one for inorganic Li +-ion conductors as reported up to date was obtained at 25 °C with an activation energy ( E a) of 0.25 eV. The enhancement in ionic conductivity of the SPS pellets was supposed mainly due to the decrease in the particle size as well as the extremely high density of the samples.