High conductive Al-free Y-doped Li7La3Zr2O12 prepared by spark plasma sintering

Al-free Li7.06La3Zr1.94Y0.06O12 (LLYZ) solid electrolyte is prepared by using the spark plasma sintering (SPS) technique. Sinterbility of LLYZ increases with sintering temperature. Well-sintered LLYZ pellet with high conductive cubic structure is obtained when SPS is performed at 1100 degrees C for 10 min. The relative density of the pellet is close to 100% and grains are not observed in the LLYZ pellet. By the high sinterbility, grain-boundary resistance can be ignored. The total conductivity of the LLYZ pellet is 9.8 x 10(-4) S cm(-1), which is higher than that of LLYZ pellet sintered the conventional method. Also, Li evaporation is suppressed by short sintering time of the SPS technique. Additionally, Al contamination, which may hinder Li ion conduction, can be avoided by using ZrO2 crucible for prearation of precursor powder and graphite die for the SPS. Therefore, low grain-boudanry resistance, high Li content and absent from Al contamination are considered to be reasons for the high Li ionic conductivity of SPS-sintered LLYZ pellet. Additionally, the LLYZ is stable in a range of 0-9.0 V vs. Li/Li+. (C) 2020 Elsevier B.V. All rights reserved.