Abstract
Dielectric ceramics with a high energy storage capacity are key to advanced pulsed power capacitors. However, conventional materials face a mutual constraint between polarization strength and the breakdown strength bottleneck. To address this limitation, the concept of nanograined high-entropy ceramics is introduced in this work. By introducing a large number of constituent elements into the A-site of perovskite material lattice, high-entropy (Bi0.2K0.2Ba0.2Sr0.2Ca0.2)TiO3-0.2 ′CuO relaxor ceramic with nanoscale grains have been successfully prepared, which breaks the mutual constraint between polarization strength and breakdown strength bottleneck and results a recoverable energy density (W rec ∼ 6.86 J/cm3) and an efficiency (η ∼ 87.7%) at 670 kV/cm. Moreover, its excellent stability makes it potentially useful under a variety of extreme conditions, including at high temperatures and high/low frequencies. These obtained results demonstrate that this nanograined high-entropy lead-free perovskite ceramic has great potential for energy storage applications.