Microstructure, dielectric, and energy storage properties of BaTiO3 ceramics prepared via cold sintering

Abstract BaTiO3 (BT) ceramics with fine grains were sintered at an ultra low temperature of 180 °C by means of a novel sintering method named as cold sintering (CS). For CS, the hydrothermal precursor solutions were incorporated into the ceramic powders, and pressure was also applied during sintering. After annealing at 900 °C, the obtained samples exhibit dense microstructures and relative densities higher than 96%. The mean size of grains in the annealed samples is as low as 122 nm. Curie temperature of the ceramics is 116 °C. Dielectric constant and dielectric loss at 1 kHz and at room temperature are 2332 and 0.01, respectively. Compared to BT ceramics synthesized via a conventional solid-state sintering method, the BT ceramics in this work show increased peak width and decreased peak value on the dielectric constant-temperature curves around Curie temperature, suggesting diffuse phase transition character. The obtained BT ceramics show high breakdown strength (90 kV/cm), high energy storage density (1.45 J/cm3), and high energy storage efficiency (85.6%). The results indicate that CS is an efficient method for low-temperature sintering BT ceramics with fine grains as well as good performance in energy storage.