Pyrochlore-based high-entropy ceramics for capacitive energy storage

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_1.5Zn_0.75Mg_0.25Nb_0.75Ta_0.75O₇ (BZMNT) bulk endows an excellent energy storage performance of W_rec ≈ 2.72 J/cm³ 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/℃) is also found to be greatly improved compared with that of the pure Bi_1.5ZnNb_1.5O₇ (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 E_b. The high-entropy design provides a new strategy for improving the high energy storage performance of ceramic materials.