Improving the energy storage performance of (Bi0.5Na0.5)TiO3–BaTiO3 based ceramics via (Sr0.7Bi0.2)TiO3 modification

Abstract

The research and development of energy storage materials and devices has now become the current hotspot. In this work, we designed high performance (0.93-x)(Bi0.5Na0.5)TiO3-0.07BaTiO3-x(Sr0.7Bi0.2)TiO3 (BNT-0.07BT-xSBT) energy storage ceramics with large recoverable energy storage density and high energy efficiency. Results showed that the introduction of SBT into BNT-0.07BT matrix improved the crystal structure symmetry of the material and induced strong relaxation behavior with broadened dielectric peak. The ferroelectric long-term order of the BNT-0.07BT matrix is destructed via SBT modification, yielding the slender P-E hysteresis loop in samples with higher SBT content. Good energy storage performance with large effective energy storage density Wrec of 3.26 J/cm3 and high energy storage efficiency η of 90.3% was obtained in 40 mol%SBT -modified sample, under the electric field of 260 kV/cm. The charge-discharge performance test showed that the sample exhibited a short discharge time (t0.9 = 143 ns) and a relatively high power density (PD = 40.8 MW/cm3) under an electric field of 160 kV/cm. Moreover, sample showed good thermal stability in the temperature range of 30–180 °C and high frequency stability in the frequency range of 1–1000 Hz. As an attractive material for dielectric capacitor, BNT-0.07BT-xSBT energy storage ceramics have potential applications in pulse power systems.