Remarkable energy-storage density together with efficiency of above 92% in high-entropy ferroelectric ceramics

Abstract

Recently, the use of “entropy engineering” to form high-entropy ceramic dielectric materials is considered to be an effective means to break through the traditional doping which modified local structures. However, the low energy storage efficiency (η) of most high-entropy ceramics cannot match their excellent energy storage density (Wrec). This work is the first to combine scheelite structure (SmTaO4) with high-entropy perovskite structure ((NaBiBaSrCa)0.2TiO3). On the one hand, the superposition of multiple structures makes the inherent lattice distortion and sluggish diffusion of high-entropy materials more obvious, thus playing a role in refining grains, reducing leakage current density, and obtaining a high breakdown electric field (Eb). On the other hand, the introduction of donor elements inhibits the generation and migration of oxygen vacancies, reducing losses to improve η and Eb. Ultimately, the goal of obtaining a remarkable Wrec (5.6 J/cm3) and η (92.2%) at 445 kV/cm was successfully achieved. This work offers a practical approach to attain superior overall performances in high-entropy ceramics.