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Journal of Advanced Ceramics

Keywords

high entropy, bismuth-based pyrochlore, high-temperature stability, energy storage

Abstract

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/℃) is also found to be greatly improved compared with that of the pure Bi1.5ZnNb1.5O7 (BZN) (~ -300 ppm/℃), 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.

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