Microwave assisted reactive sintering for Al doped Li₇La₃Zr₂O₁₂ lithium ion solid state electrolyte

Li_6.28Al_0.24La₃Zr₂O₁₂ (Al-LLZO) solid electrolyte for Li-ion battery was prepared by a microwave-assisted reactive sintering (MARS) method. When sintered by the MARS method, the Al-LLZO cubic phase formed at 1000 °C, which is 100 °C lower than that in a conventional furnace sintering method. With the increase of sintering temperature and holding time in MARS, the relative density of Al-LLZO samples goes up. Also, the improved conductivity is related to the decrease of pore number between Al-LLZO grains. And the reduced grain boundary resistivity contributes the most to total reduced resistivity compared with the grain resistivity. The Li-ion conductivity of the Al-LLZO samples prepared by MARS at 1200 °C for 3 h reaches 1.06 × 10^{−4 s} cm⁻¹ at 25 °C and the value of conduction activation energy is 0.36 eV at 25–150 °C. (paper)