Enhanced densification and ionic conductivity of LLZO by flash sintering

ABSTRACT

Flash sintering arouses the interest since high-density ceramics can be obtained at shorter dwell times and lower temperatures than conventional sintering. In this study, the cubic garnet Li_6.25Al_0.25La₃Zr₂O₁₂ (Al-LLZO) was successfully synthesised by the solid-state method. The powders were uniaxially pressed and were subjected to flash sintering at 850°C in a tube furnace under a DC bias using various current densities. It is evidenced that control of the flash electric current is a crucial factor for densification of Al-LLZO. The sample sintered in 50 V cm⁻¹ and 200 mA mm⁻² showed a cubic LLZO, 94 ± 0.4% relative density, 0.37 mS cm⁻¹ total ionic conductivity and 0.32 eV activation energy. In addition, it was demonstrated that increasing the current density had a considerable impact on the relative density. This outstanding ionic conductivity might be due to the lower lithium loss and higher density as a result of flash sintering method applied.

KEYWORDS:

• Garnet
• LLZO
• lithium loss
• flash sintering
• solid-state batteries

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work is based upon research funded by Iran National Science Foundation (INSF) under project No. 4000823.