Fast synthesis of Na2Ti3O7 system synthesized by microwave-assisted hydrothermal method: Electrical properties

Sodium titanate Na2TinO2n+1 (2 <= n <= 9) is a well-known semiconductor that exhibits interesting electrical properties allowing numerous applications, such as: electrodes for solid-state batteries. In this work, we reported a novel, fast and simple route to produce sodium titanate (Na2Ti3O7 - NT) structures at low temperature and short time, by using microwave-assisted hydrothermal method. The NT powder synthesis was performed at 200 degrees C for 1 h and 4 h. Afterward, the as-synthetized powders were sintered to 900 degrees C for 1 h. The samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and complex impedance spectroscopy. It was identified a phase mixture of the polymorphs Na2Ti3O7 and Na2Ti6O13 with elongated rod-like morphology. Both samples showed a majority Na2Ti3O7 (>= 95%) crystalline phase, as confirmed by Rietveld refinement. After ceramics sintering the total dc conductivity values between of 10(-6) S/cm and 10(-7) S/cm were achieved.