Dielectric ceramics are crucial for high-temperature, pulse-power energy storage applications. However, the mutual restriction between the polarization and breakdown strength has been a significant challenge. Here, multiphase engineering controlled by the two-step sintering heating rate is adopted to simultaneously obtain a high polarization and breakdown strength in 0.8(0.95Bi 0.5 Na 0.5 TiO 3 − 0.05SrZrO 3 )−0.2NaNbO 3 (BNTSZNN) ceramic systems. The coexistence of tetragonal (T) and rhombohedral (R) phases benefits the temperature stability of BNTSZNN ceramics. Increasing the heating rate during sintering reduces the diffusion of SrZrO 3 and NaNbO 3 into Bi 0.5 Na 0.5 TiO 3 , which results in a high proportion of the R phase and a finer grain size. The overall polarization is enhanced by increasing the proportion of the high-polarization R phase, which is demonstrated using a first-principles method. Meanwhile, the finer grain size enhances the breakdown strength. Following this design philosophy, an ultrahigh W dis of 5.55 J/cm 3 and η above 85% is achieved in BNTSZNN ceramics as prepared with a fast heating rate of 60 °C/min given a simultaneously high polarization of 43 μC/cm 2 and high breakdown strength of 350 kV/cm. Variations in the discharge energy density from room temperature to 160 °C are less than 10%. Additionally, such BNTSZNN ceramics exhibit an ultrafast discharge speed with τ 0.9 at approximately 60 ns, which shows great potential in pulse-power system applications.

No abstract

No abstract

No abstract

No abstract