Pyrochlore-based high-entropy ceramics for capacitive 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 Bi 1.5 Zn 0.75 Mg 0.25 Nb 0.75 Ta 0.75 O 7 (BZMNT) bulk endows an excellent energy storage performance of W rec ≈ 2.72 J/cm 3 together with an ultra-high energy efficiency of 91% at a significant enhanced electric field E b 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 Bi 1.5 ZnNb 1.5 O 7 (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 E b . The high-entropy design provides a new strategy for improving the high energy storage performance of ceramic materials.