Remarkable energy storage capability and dielectric temperature stability in (Na0.5Bi0.5)TiO3-based medium entropy superparaelectrics

Eco-friendly dielectric ceramics with excellent energy storage performance and dielectric temperature stability are the kernel parts of pulsed power devices in the next-generation. However, the contradiction between high breakdown electric field ( E b )and maximum polarization ( P max ) restricts the improvement of comprehensive performance. Herein, we report a novel strategy of entropy engineering in the superparaelectric state to address the above concerns. On the one hand, near-linear polarization response can be achieved in the superparaelectric state, which can be beneficial to obtain a large P max , low remnant polarization ( P r ) and slim P-E loops. On the other hand, the improvement of configuration entropy (Δ S config ) is conducive to refining grain size and domain size, enhancing bandgap width, and suppressing leakage current and interfacial polarization, thus the generation of large E b . Therefore, with the Δ S config increases from 0.98 R to 1.44 R, a giant energy storage density ( W rec ) of 8.11 J/cm 3 as well as a high efficiency ( η ) of 90.2 % are synchronously obtained. Significantly, the optimum sample shows outstanding dielectric temperature stability (Δ C / C 25°C ≤ ± 15 %, −55 ∼ 165 °C) in accordance with X8R. This work demonstrates that the medium entropy superparaelectrics are a shortcut to achieve next-generation ceramic capacitors with high comprehensive performance.