Achieving excellent energy storage properties and temperature stability in BNT-BT-BS ceramics under low electric field

Bi 0.5 Na 0.5 TiO 3 -BaTiO 3 (BNT-BT) relaxor ferroelectric system has been highly regarded for its superior performance. BiScO 3 (BS) component was added into BNT-BT to construct medium entropy (1.53R < 1.61R) ternary ferroelectric ceramics for the excellent energy storage performance. The effect of BS on the energy storage performance for BNT-BT ceramics were investigated systematically. Indeed, the introduction of BS causes the reduction of ferroelectric long-range order and delayed polarization saturation, which results from a higher maximum polarization ( P max ) and reduced remanent polarization ( P r ) after the increase of entropy value. Meanwhile, twice firing porcelain method was employed to refine the grains and improve the breakdown electric field strength ( E b ). Currently, E b of the 0.60BNT-0.21BT-0.19BS (BNT-BT-0.19BS) ceramic are improved to 200 kV/cm, the recoverable energy density W re c is 4.22 J/cm 3 , and the efficiency η is 86.83 %. It also maintains excellent temperature stability ( ΔW rec %≤2.2 % within the temperature range of 25 ∼ 150 °C) and fatigue resistance ( ΔW rec  ≤ 0.03 J/cm 3 after 10 6 cycles). Especially, BNT-BT-0.19BS ceramic has good charging-discharging characteristics, with a t 0.9 of 84 ns at room temperature. Appropriate increase of ΔS config in ferroelectrics is beneficial for improving energy storage characteristics, this provides guidance for designing high-performance lead-free dielectric energy storage materials.