Structural and electrical properties of spinel Al³⁺ doped Li₄Ti₅O₁₂

Spinel Li_4.25Al_0.25Ti_4.75O₁₂ (LATO) was successfully synthesized by the sol-gel route and was characterized using x-ray diffraction (XRD), scanning electron microscopy (SEM), and complex impedance spectroscopy. Rietveld analysis of XRD data confirmed the formation of phase pure spinel structure with space group Fd3̄m. SEM analyses indicated that the LATO ceramics sintered at 800 °C has a dense microstructure with average grain size of ∼1 µm. Impedance responses of the LATO sample were rationalized using the equivalent circuit modeling. The conductivity of LATO sample was found to be ≈ 1.88 × 10^-7 Scm^-1 at room temperature with an associated DC conduction activation energy ∼0.71 eV.