One-step solid-state reactive sintering with Li2CO3 as an intrinsic sintering aid for Al-doped Li7La3Zr2O12 solid-state battery electrolytes

Although some advanced techniques, such as spark plasma sintering, hot sintering, and flash sintering, have demonstrated the successful processing of Li 7 La 3 Zr 2 O 12 -based solid-state battery electrolytes, the cost-effective and simple sintering method is still worthy of pursuing. In this work, a one-step solid-state reactive sintering (SSRS) method was employed to fabricate 30 mol% Al-doped Li 7 La 3 Zr 2 O 12 (LLZAO) pellets directly using an additional 10 wt% Li 2 CO 3 without the powder synthesis step. The evolution of the crystal structure and microstructure of LLZAO pellets was investigated by varying sintering temperature and time between 1100 −1200 °C and 2 −8 h, respectively. The LLZAO pellet at 1175 °C for 2 h demonstrates the best cubic Li 7 La 3 Zr 2 O 12 purity over 96.3 % and the highest relative density close to 90 % and achieves an average grain size of around 10 µm. A conductivity of 1.28 × 10 −5 S˖cm −1 was obtained at room temperature, which, although lower than the recent state-of-the-art LLZO pellets sintered using mature advanced techniques, demonstrates that the SSRS may offer a new, cost-effective, and straightforward method for fabricating Li 7 La 3 Zr 2 O 12 -based electrolytes for solid-state batteries.