Enhanced energy-storage performance and temperature-stable dielectric properties of (1 − x)(0.94Na _0.5 Bi _0.5 TiO ₃ –0.06BaTiO ₃ )–xNa _0.73 Bi _0.09 NbO ₃ ceramics

A series of novel (1 − x)(0.94Na _0.5 Bi _0.5 TiO ₃ –0.06BaTiO ₃ )–xNa _0.73 Bi _0.09 NbO ₃ (BNT–BT–100xNBN) (x = 0–0.15) lead-free ceramics were fabricated by conventional solid state reaction method. The effects of NBN modification on the phase evolution, dielectric behavior, ferroelectric property and energy-storage performance were comprehensively investigated. All samples showed the pseudocubic structure and excessive dopants resulted in the secondary phase. The introduction of NBN resulted in deteriorative relaxor properties and maked two distinct dielectric anomalies smeared mutually. Therefore, the sample with x = 0.10 displayed a high permittivity (~ 1988) and low dielectric loss (< 0.02) in a broad temperature range of 25–337 °C. In addition, when x = 0.1, the optimal energy-storage density W _rec reached up to 1.56 J/cm ³ with energy efficiency η = 92.5% at 120 kV/cm. The excellent thermal stability and fatigue resistance of sintered ceramics make it possible to be applied for practical dielectric capacitors.