Preparation of nanocrystalline LiNbO3 through aqueous solution process using peroxo-polyniobic acid

Abstract

Nanocrystalline lithium niobate, LiNbO3, is prepared through an aqueous solution process starting from the reaction between H2O2 aq and NbC to form a peroxo-polyniobic acid solution. An amorphous lithium niobate is obtained by mixing LiOH aq with the peroxo-polyniobic acid solution and drying it at 115 °C. The amorphous lithium niobate transforms into crystalline LiNbO3 by heating at 400–500 °C for 1–24 h in air. Rietveld analysis of the XRD patterns indicates that the crystal structure of LiNbO3 is the same as the conventional LiNbO3 - type structure with the space group R 3 c and that the crystallite size is about 28 nm. The nanocrystalline LiNbO3 prepared at 500 °C shows an ionic conductivity of 7.2 × 10−6 Scm−1 in a complex impedance plot.