(Nb+Al) co‐doped SrTiO3 ceramics with a nominal composition of Sr(Nb0.5Al0.5)xTi1‐xO3 (x = 0, 0.02, 0.04, and 0.06) were fabricated using the conventional solid‐state reaction method; giant permittivity (10500) and low dielectric loss (0.03) were obtained at x = 0.06. Dielectric and impedance spectroscopy, X‐ray photoelectron spectroscopy, and Raman spectroscopy, were employed to study why the dielectric property improved. The results indicate that the giant dielectric response occurs because of the combined effects of the off‐center Ti3+ reorientation and conduction of electrons with the polar ordering structure Ti3+/Ti4+. In contrast, the low dielectric loss can be attributed to electron localization that occurs because of the defect dipole ][Ti4+·e−Vo··−Ti4+·e. These fundamental understandings will benefit the design of doped SrTiO3 ceramics with desired performance.

High-performance dielectrics are widely used in high-power systems, electric vehicles, and aerospace, as key materials for capacitor devices. Such application scenarios under these extreme conditions require ultra-high stability and reliability of the dielectrics. Herein, a novel pyrochlore component with high-entropy design of Bi1.5Zn0.75Mg0.25Nb0.75Ta0.75O7 (BZMNT) bulk endows an excellent energy storage performance of Wrec ≈ 2.72 J/cm3 together with an ultra-high energy efficiency of 91% at a significant enhanced electric field Eb of 650 kV/cm. Meanwhile, the temperature coefficient (TCC) of BZMNT (∼−220 ppm/°C) is also found to be greatly improved compared with that of the pure Bi1.5ZnNb1.5O7 (BZN) (∼−300 ppm/°C), demonstrating its potential application in temperature-reliable conditions. The high-entropy design results in lattice distortion that contributes to the polarization, while the retardation effect results in a reduction of grain size to submicron scale which enhances the Eb. The high-entropy design provides a new strategy for improving the high energy storage performance of ceramic materials.

No abstract

No abstract

No abstract