Grain size engineered (Ba,Sr)(Zr,Ti)O3 ceramics with excellent energy storage properties for high-voltage pulsed capacitors

The macroscopic physical properties of functional ceramics are strongly affected by grain morphology, almost resulting from the sintering process. For a given ceramic material, it has been experimentally confirmed that the enhancement of dielectric breakdown strength Eb can largely increase energy storage density (W). An effective method to increase Eb of ceramic materials is the control of grain morphology. Herein, the (Ba0.95Sr0.05)(Zr0.2Ti0.8)O3 ceramics have been intensively investigated by different sintering techniques to improve grain morphology. Compared with single-step sintering, two-step sintering can sharply inhibit grain growth and make size distribution uniform, which is conducive to the increase in the Eb. A competitive energy storage capacity can be achieved with a high Wch of 3.78 J/cm3, a high Wdi of 3.50 J/cm3, and a high η of 92.6% by two-step sintering due to large Eb of 350 kV/cm, accompanied with good thermal stability till to 160 °C and good fatigue characteristics up to 105 cycles, indicating that two-step sintering is an effective strategy of engineering grain morphology.