Enhanced energy storage density with excellent temperature-stable dielectric properties of (1-x)[(Bi0.5Na0.5)0.94Ba0.06TiO3]-xAgNbO3 lead-free ceramics

Abstract

Lead-free (1-x)[(Bi0.5Na0.5)0.94Ba0.06TiO3]-xAgNbO3 (abbreviated as BNTBT-100xAN) ceramics were fabricated using a conventional solid-phase reaction technique. The effect of the antiferroelectric AgNbO3 dopants for fatigue resistance, energy-storage density, temperature-stable permittivity, and conductivity mechanism was systematically investigated. The addition of AgNbO3 led to the decrease of remnant polarization and the increase of dielectric breakdown strength, a large effective energy-storage density of ~1.27 J/cm3 corresponding to the conversion efficiency of ~ 77.5% for BNTBT-5AN ceramic were attained under applied 105 kV/cm field. Meanwhile, it exhibited an outstanding fatigue-resistant performance at 70 kV/cm fixed field up to 105 cycles accompanied with excellent temperature-stable properties in the temperature range of 30 °C ~ 120 °C. Besides, BNTBT-5AN sample has also obtained outstanding temperature-stable permittivity, which was associated with the enhancement of the ergodic relaxor domain structure. A little variance of dielectric content (Δε'/ε'150 °C ≤ ± 15%) was acquired from 40 °C to 387 °C with a small tangent loss (tanδ ≤ 0.05) between 50 °C and 461 °C. Hence, it revealed that the high energy storage properties and excellent dielectric temperature stability for BNTBT-5AN ceramic were conducive to its better applications in electronic equipment.