Thermal behavior of the nonstoichiometric lithium niobate powders synthesized via a combustion method

Lithium niobate (LixNb1−xO3+δ) powders with various compositions are prepared via combustion synthesis. The thermal properties, crystal structure, and surface morphology of the as-prepared lithium niobate powders are characterized by thermogravimetric and differential thermal analyses (TG/DTA), powder X-ray diffraction (XRD), and scanning electron microscopy (SEM). When the calcination temperature reached 900 °C, the secondary phases Li3NbO4 and LiNb3O8 were observed. The lithium concentration before 900 °C was 40–43%. The lattice parameters increased slightly with decreasing concentration of lithium ions. When the calcination temperature was higher than 900 °C, the major Li0.91NbO3 phase and the minor LiNbO3 phase coexisted in the nonstoichiometric lithium niobate with 43% lithium content.