Improvement of sintering of Li6.25Al0.25La3Zr2O12 by using pre-heat treatment

An improvement of sintering process for Li6.25Al0.25La3Zr2O12 (Al-LLZ) pellet was investigated. Based on a phase transformation of Al-LLZ precursor during heating process, the sintering process of AL-LLZ pellet was discussed. The ball milled fine Al-LLZ precursor consisted of Al-LLZ with low temperature cubic garnet structure and Li2CO3 as an impurity. The crystal structure of the ball milled Al-LLZ precursor was changed during the heating process. After the heat treatment at 900 °C, Al-LLZ precursor was converted to garnet structure without any impurity. A grain boundary of Al-LLZ pellet sintered at 1150 °C with the heat treatment process at 900 °C for 3 h was reduced, compared with that prepared without pre-heat treatment at 900 °C. In this way, the sintering of Al-LLZ pellet was improved by using the pre-heat treatment due to low content of carbonate species and low temperature garnet structure formation.