Synergistic optimization of delayed polarization saturation and enhanced breakdown strength in lead-free capacitors for superior energy storage characteristics

High-performance dielectric energy-storage ceramics are indispensable core components in pulsed power systems. Despite progress in enhancing energy storage performance, there are still significant constraints among various macroscopic performance parameters, hindering their miniaturization and integration into devices. Herein, we propose a novel weakly coupled relaxor ferroelectric ceramic system that delays premature polarization saturation of BaTiO 3 -based ceramics to achieve the desirable energy storage characteristics. The ceramic exhibits a high energy storage density ( W rec ) of ∼4.58 J cm −3 and high energy efficiency ( η ) of ∼95.2 % under an electric field of 540 kV cm −1 , along with good performance stability in the range of 40–160 °C and 1–120 Hz. Furthermore, the enhanced insulation properties and refined average grain size contribute to the high breakdown field strength ( E b ) of the system. These findings provide a viable framework for the design of dielectric ceramic capacitors with high energy-storage characteristics.