Lithium ion conductivity, crystallization tendency, and microstructural evolution of LiZrxTi۲-x(PO۴)۳ NASICON glass-ceramics (x = ۰ - ۰.۴)

In this research, NASICON type (LiZrXTi۲-X(PO۴)۳) glass-ceramics were fabricated (x = ۰.۱, ۰.۲, ۰.۳, ۰.۴). Lithium-ion conductivity along with the crystallization tendency and microstructural features were examined in this regard. Parent glasses obtained through melt quenching were converted to the glass-ceramic specimens after one-step heat treatment procedure. The resultant glass-ceramics were deeply explored by means of different techniques including scanning electron microscope, differential thermal analysis, X-ray diffractometry, and ionic conductivity measurements. According to the obtained results, presence of Zr۴+ ions in the glass network and its gradual increase caused the enhanced crystallization temperature as well as declined crystallinity and microstructure coarsening. In all studied glass-ceramics, LiT۲(PO۴)۳ solid solution was the dominant crystalline phase and Zr۴+ ions partly substituted in the structure of this crystalline phase. Moreover, presence of Zr۴+ ions in the glass composition resulted in diminished lithium-ion conductivity of corresponded glass-ceramics at ambient temperature. Consequently, total conductivity of specimen with the highest level of ZrO۲ (x = ۰.۴) was measured to be ۰.۷۸ x ۱۰-۵ Scm-۱, being considerably less than ionic conductivity of the base (x = ۰) glass-ceramic (۳.۰۴ x ۱۰-۵ Scm-۱). It seems that less crystallinity of ZrO۲ containing glass-ceramics decreases required connectivity between the lithium-ion free paths and is responsible for the diminished ionic conductivity of these specimens.In this research, NASICON type (LiZrXTi۲-X(PO۴)۳) glass-ceramics were fabricated (x = ۰.۱, ۰.۲, ۰.۳, ۰.۴). Lithium-ion conductivity along with the crystallization tendency and microstructural features were examined in this regard. Parent glasses obtained through melt quenching were converted to the glass-ceramic specimens after one-step heat treatment procedure. The resultant glass-ceramics were deeply explored by means of different techniques including scanning electron microscope, differential thermal analysis, X-ray diffractometry, and ionic conductivity measurements. According to the obtained results, presence of Zr۴+ ions in the glass network and its gradual increase caused the enhanced crystallization temperature as well as declined crystallinity and microstructure coarsening. In all studied glass-ceramics, LiT۲(PO۴)۳ solid solution was the dominant crystalline phase and Zr۴+ ions partly substituted in the structure of this crystalline phase. Moreover, presence of Zr۴+ ions in the glass composition resulted in diminished lithium-ion conductivity of corresponded glass-ceramics at ambient temperature. Consequently, total conductivity of specimen with the highest level of ZrO۲ (x = ۰.۴) was measured to be ۰.۷۸ x ۱۰-۵ Scm-۱, being considerably less than ionic conductivity of the base (x = ۰) glass-ceramic (۳.۰۴ x ۱۰-۵ Scm-۱). It seems that less crystallinity of ZrO۲ containing glass-ceramics decreases required connectivity between the lithium-ion free paths and is responsible for the diminished ionic conductivity of these specimens.

کلیدواژه ها:

Glass-ceramic ، Crystallization ، Ionic conductivity ، Zirconium ions ، NASICON