Mechanism of template-directed formation of highly-oriented polycrystalline barium titanate nanoplates from barium glycolate

BaTiO₃ nanomaterials with anisotropic shapes are of significant interest for electronic and energy storage applications due to their unique dielectric and piezoelectric properties, along with their potential as targets for 2D ferroelectrics. However, the mechanisms underlying the formation of such nanostructures remain insufficiently explored. To address this gap, we investigate the mechanism of the transformation of glycolate-based template into barium titanate ((BaTiO₃) polycrystalline nanoplates during heat treatment. Here, we demonstrate that using a crystalline glycolate-based plate-shaped template enables the production of highly oriented polycrystalline BaTiO₃ nanoplates through calcination at 720 ⁰C. The resulting nanoplates exhibit sizes around 1μmx1μm, with a slight tetragonal unit cell distortion, and an average crystal misorientation angle of 1.8–2.0°. Transmission Kikuchi Diffraction (TKD) demonstrates that crystallites within each platelet are preferentially oriented along the [111] direction. This, along with the retention of particle shape, indicates an in-situ topotactic transformation, which is characterized by accelerated growth kinetics at the edges of the particles relative to the interior. The formation of BaTiO₃ from the 2D template matrix facilitates both homogeneous nucleation and crystallographic alignment. Thus, the mechanism involves template-directed growth. By integrating hydrothermal synthesis with the calcination step, we can independently adjust the polycrystal dimensions and grain sizes by tuning synthesis parameters and calcination mode, respectively. This work provides new insights into the interplay of synthesis conditions, structural evolution, and the underlying physical chemistry of BaTiO₃ formation, offering potential routes for tailoring nanomaterials for specific applications in electronics and energy storage.