Entropy engineering of BF-BT-based high-entropy ceramics for ultra-high energy storage performance

Abstract

Dielectric capacitors are promising for pulsed power applications, but the energy storage performance of lead-free bulk ceramics is often limited by low breakdown strength and large ferroelectric hysteresis. Herein, a high entropy perovskite oxide BaTi0.2Zr0.2Sn0.2Hf0.2Nb0.1Sc0.1O3 was introduced into the BF-BT matrix to develop lead free high entropy ferroelectric ceramics. Multicomponent B-site substitution induces lattice distortion, enhanced pseudocubic characteristics, relaxor behavior, and grain refinement. These effects suppress polarization hysteresis and electrical conduction, resulting in a significant increase in breakdown strength. A maximum breakdown strength of 840 kV/cm1 and a recoverable energy density of 10.55 J/cm3 were achieved. Entropy-induced microstructural heterogeneity promotes a more uniform electric-field distribution and delays dielectric breakdown. This work demonstrates entropy engineering as an effective route to achieving high breakdown strength and superior energy-storage performance in lead-free ferroelectric ceramics.