Enhanced Li‐ion Conductivity of Li7La3Zr2O12 by Simultaneous Substitution of Aluminum and Niobium Using a Modified Sol–gel Method

Abstract By increasing technical demand for long‐lasting and safer batteries against thermal explosion, garnet‐type cubic phase Li7La3Zr2O12 (LLZO) is a promising solid electrolyte as a next‐generation advanced battery. In this work, we studied Al and Nb co‐doped Li6.25–yAl0.25La3Zr2–yNbyO12 (0 ≤ y ≤ 0.30) electrolytes prepared using a modified sol–gel method. X‐ray diffraction and electrochemical analyses probed the synergistic effect of Al and Nb simultaneous substitution on the microstructure and ionic conductivity. In conclusion, an optimal amount of Al and Nb enhances densification and ionic conductivity, and then Li6Al0.25La3Zr1.75Nb0.25O12 achieves the highest relative density of 94% and total ionic conductivity of 5.41 × 104 S cm−1 at 30°C.