Improved Li-Ion conduction by ion-conductor Li1.5Al0.5Ge1.5(PO4)3 additive in garnet type Li7La3Zr2O12 solid electrolytes

In this study, Li1.5Al0.5Ge1.5(PO4)(3) (LAGP) was introduced as a sintering aid up to 4 wt % into the garnet type Li7La3Zr2O12 (LLZO) structure. Results pointed out that increasing LAGP amount improved densification and electrochemical performance comparing with pure LLZO. But, LAGP addition facilitated the open pore formation and cracking occurred eventually. 1 wt % LAGP containing LLZO was optimized as they show the best electrolytic properties with 0.78 mS/cm ionic conductivity and 1.25 x 10(-7) S/cm electronic conductivity without suffering from the open pore formation. LAGP added LLZO samples exhibited one of the lowest activation energies around 0.17 eV when compared to the pure LLZO (0.24 eV) as LAGP stayed between LLZO grains and maintain the continuous ion-conductive pathway. Considering all of the findings, the study offers a new approach to obtain bulk type LLZO solid electrolytes with the lowest activation energy thanks to the inter-granular ion conduction.

Automated summary

In this study, Li1.5Al0.5Ge1.5(PO4)(3) (LAGP) was introduced as a sintering aid into the garnet type Li7La3Zr2O12 (LLZO) structure. The addition of LAGP improved the densification and electrochemical performance of LLZO, but also led to the formation of open pores and cracking. The optimized LLZO sample with 1 wt % LAGP showed the best electrolytic properties and a lower activation energy, thanks to the continuous ion-conductive pathway facilitated by LAGP.