High-entropy superparaelectrics enhanced capacitive energy storage

Lead-free dielectric ceramics are considered pivotal for next-generation pulsed power capacitors, yet their low energy storage density critically impede progress toward high-performance and miniaturized devices. Herein, we design high-entropy superparaelectrics in lead-free perovskite ceramics to enhance energy storage properties. This strategy can induce the formation of small-sized nanodomains, multiple types of oxygen octahedral tilts, and refined grain microstructures, collectively enabling rapid polarization response, delayed polarization saturation, large polarization difference, and enhanced breakdown electric field. By leveraging this design, an outstanding recoverable energy density of 14.7 J cm⁻³ is achieved in the 1/3NaNbO₃-1/3Bi_0.5Na_0.5TiO₃-1/3SrTiO₃ lead-free ceramic under an ultrahigh breakdown field of 78 kV mm⁻¹, accompanied by excellent frequency and temperature stability as well as superior pulsed charge-discharge performance. This work demonstrates that designing high-entropy superparaelectrics is an effective approach to enhance energy storage properties, offering significant potential for advanced energy storage applications.