Excellent energy storage properties realized in novel BaTiO3-based lead-free ceramics by regulating relaxation behavior

TLDR

BaTiO3 is a promising lead‑free ferroelectric, yet its large remanent polarization and coercive field hinder energy‑storage performance. By incorporating BZH (Bi(Zn0.5Hf0.5)O3) into BaTiO3, the authors tailor the phase structure and grain size, producing ceramics with high breakdown strength and enhanced relaxation behavior. The resulting 0.88BT‑012BZH relaxor exhibits a recoverable energy density of ~3.62 J cm⁻³, an efficiency of ~88.5 %, excellent thermal (25–115 °C) and frequency (1–500 Hz) stability, and ultrafast charge‑discharge characteristics (100 ns, 1.2 J cm⁻³, 31.1 MW cm⁻³), indicating a promising lead‑free energy‑storage platform.

Abstract

BaTiO3(BT) has attracted extensive attention among advanced lead-free ferroelectric materials due to its unique dielectric and ferroelectric properties. However, the enormous remanent polarization and coercive field severely impede the improvement of its energy storage capabilities. Here, the BaTiO3Bi(Zn0.5Hf0.5)O3 (BT-BZH) ceramics with high breakdown field strength and remarkable relaxation characteristics can be obtained by introducing the composite component BZH in BT to regulate the phase structure and grain size of the ceramics. The findings demonstrate that the improvement of energy storage performance is related to the increase of relaxation behavior. A large energy storage density (Wrec∼3.62 J/cm3) along with superior energy storage efficiency (η∼88.5%) is achieved in 0.88BT-0.12BZH relaxor ceramics only at 240 kV/cm. In addition, the sample suggests superior thermal stability and frequency stability within 25–115 °C and 1–500 Hz, respectively. Furthermore, the outstanding charge-discharge properties with an ultrafast discharge time (100 ns), large discharged energy density (1.2 J/cm3), impressive current density (519.4 A/cm2) and power density (31.1 MW/cm3) under the electric field of 120 kV/cm are achieved in studied ceramics. The excellent energy storage performance of BT-BZH ceramics provides a promising platform for the application of lead-free energy-storage materials.