Impact of synthesis route on the microstructure and energy-storage properties of (Bi1/2K1/2)TiO3-SrTiO3 relaxor ferroelectric ceramics: Solid-state and hydrothermal approaches

Bismuth potassium titanate (Bi1/2K1/2)TiO3-based relaxor ferroelectrics are promising materials for high-energy density ceramic capacitors. Herein, we compare the microstructure and energy-storage properties of (Bi1/2K1/ 2)0.5Sr0.5TiO3 (BKST50) ceramics fabricated via two different routes: solid-state and hydrothermal reactions. A BKST50 fine powder composed of well-dispersed cubic nanoparticles was obtained via the hydrothermal reaction, whereas the conventional solid-state reaction resulted in the aggregation of primary particles. The grain size of the ceramics prepared from the hydrothermal powder could be controlled between 273 & PLUSMN; 24 and 936 & PLUSMN; 69 nm while maintaining a relative density of over 95% by simply varying the sintering temperature. On the other hand, ceramics prepared via the solid-state reaction could not be fully densified even at 1200 degrees C (the highest tested sintering temperature). The hydrothermally derived ceramics withstood higher electric field owing to dense and fine-grained microstructure, leading to a high recoverable energy-storage density of 2.25 J cm-3 at 240 kV cm-1.

Automated summary

We compared the microstructure and energy-storage properties of (Bi1/2K1/ 2)0.5Sr0.5TiO3 ceramics prepared via solid-state and hydrothermal reactions. The hydrothermally derived ceramics exhibited well-dispersed cubic nanoparticles, while the solid-state reaction resulted in the aggregation of primary particles. By controlling the sintering temperature, the grain size of the hydrothermally derived ceramics could be controlled between 273±24 and 936±69 nm, maintaining a relative density of over 95%. On the other hand, ceramics prepared via the solid-state reaction did not fully densify even at the highest tested sintering temperature of 1200 degrees C. The hydrothermally derived ceramics exhibited a high recoverable energy-storage density of 2.25 J/cm^3 at 240 kV/cm, attributed to their dense and fine-grained microstructure.