Microwave-assisted solvothermal synthesis of nanostructured Ga-Doped Li7La3Zr2O12 solid electrolyte with enhanced densification and Li-ion conductivity

초록

Garnet-type Li7La3Zr2O12 (LLZO) Li-ion solid electrolytes are promising candidates for safe, nextgeneration solid-state batteries. In this study, we synthesize Ga-doped LLZO (Ga-LLZO) electrolytes using a microwave-assisted solvothermal method followed by low-temperature heat treatment. The nanostructured precursor (<50 nm) produced by the microwave-assisted solvothermal process has a high surface energy, facilitating the reaction for preparing garnet-type Ga-LLZO powders (<800 nm) within a short time (<5 h) at a low calcination temperature (<700 degrees C). Additionally, the calcined nanostructured Ga-LLZO powder can be sintered to produce a highdensity pellet with minimized grain boundaries under moderate sintering conditions (temperature: 1150 degrees C, duration: 10 h). The optimal doping concentration was determined to be 0.4 mol% Ga, which resulted significantly increased the ionic conductivity (1.04 x 10(-3) S cm(-1) at 25 degrees C) and stabilized the cycling performance over 1700 h at 0.4 mA cm(-2). This approach demonstrates the potential to synthesize oxide-type solid electrolyte materials with improved properties for solid-state batteries.

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