Ba2+/Sr2+ regulation in A‐site vacancy‐engineered B0.015+1.5xS0.245‐1.5x□0.03BNT relaxor ceramics for energy storage

Abstract

AbstractA‐site vacancy‐engineered Ba0.015+1.5xSr0.245‐1.5x□0.03Bi0.385Na0.325TiO3 (B0.015+1.5xS0.245‐1.5x□0.03BNT, x = 0, 0.012, 0.024, 0.036, 0.048, 0.06) ceramics were fabricated by a solid‐state reaction method. The effect of Ba/Sr regulation on the structure, polarization, and dielectric energy storage properties of the B0.015+1.5xS0.245‐1.5x□0.03BNT ceramics were investigated. With the increase of the x value, the lamellar microdomains transform into the coexistence of banded domains and nanodomains. A double‐like P‐E hysteresis loop with a high polarization value (Pmax > 35 μC/cm2) can be obtained at a very low electric field of 60 kV/cm. Consequently, a large recoverable energy storage density (Wrec = 2.33 J/cm3) can be achieved at a relatively low applied electric field of 130 kV/cm. The designed B0.087S0.173□0.03BNT also exhibits high dielectric constant (εr = 3510 @150°C&1 kHz) with suitable temperature capacitance coefficient (TCC150°C = ±15%) over the temperature range of 17°C∼382°C. These findings provide a novel vacancy‐engineered avenue towards the design of BSBNT relaxor ceramics with high Wrec and good stability for low‐voltage driven high‐temperature pulsed power capacitor.