High energy storage properties and dielectric temperature stability of (1-x)(0.8Bi0.5Na0.5TiO3-0.2Ba0.3Sr0.7TiO3)-xNaNbO3 lead-free ceramics

Perovskite structure (1-x)(0.8Bi0.5Na0.5TiO3-0.2Ba0.3Sr0.7TiO3)-xNaNbO3 (BNBST-xNN, x ≤ 0.3) ceramics were fabricated by solid-state reaction method. The grain growth was suppressed after adding NaNbO3 into 0.8Bi0.5Na0.5TiO3-0.2Ba0.3Sr0.7TiO3 ceramic, and XRD patterns revealed that solid solutions were formed with NaNbO3 at 0–0.2. With the rising amount of NaNbO3, both relaxor characteristics and dielectric temperature stability were enhanced. The BNBST-0.1NN solid solution displayed a high recoverable energy storage density of 2.26 J/cm3 with energy storage efficiency of 87.34% at 180 kV/cm and exhibited a short time of less than 1 μs for discharged energy density reached to 90% of its saturated value. Furthermore, the ceramic for x = 0.1 displayed a permittivity of 2601 at 150 °C and showed a wide range from 20 to 300 °C for permittivity deviation Δε/ε150°C less than ±15%, exhibiting a superior thermal stability of permittivity. In addition, a reduction around 5% in Wdis after 106 cycles indicated its excellent fatigue characteristics. •Lead-free BNBST-xNN ceramics for energy storage were successfully prepared.•A high releasable energy storage density of 2.26 J/cm3 was obtained.•BNBST-0.1NN ceramic exhibited good thermal stability and frequency stability.•The energy storage density of BNBST-0.1NN is degraded around 5% after 106 cycles.