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

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-0.07BTxSBT) 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 eta 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 degrees 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.