Ultrafast high-temperature sintering of Li7La3Zr1.75Nb0.25Al0.15O12 (LLZO)

Rapid sintering of Li7La3Zr1.75Nb0.25Al0.15O12 (LLZO) is reported. The selection of heating elements, the effect of powder preparation and MgO additions in rapid sintered LLZO are described. Annealing LLZO powder at 750 ºC for 2 h in argon immediately before pressing helped to minimize porosity. A 15–20 s hold at 1372 ºC was sufficient to achieve densities >97%. The total sintering schedule time for rapid sintering represents a 99.7% decrease in sintering time compared to conventional sintering. At 70 °C under a pressure of 4.12 MPa cells had a critical current density of 1020 µA/cm2.