Achieving High Energy Storage Performance under a Low Electric Field in KNbO 3 -Doped BNT-Based Ceramics.

Ceramic capacitors have great potential for application in power systems due to their fantastic energy storage performance (ESP) and wide operating temperature range. In this study, the (1 - x )Bi 0.5 Na 0.47 Li 0.03 Sn 0.01 Ti 0.99 O 3 - x KNbO 3 (BNLST- x KN) energy storage ceramics were synthesized through the solid-phase reaction method. The addition of KN disrupts the long-range ferroelectric order of the BNLST ceramic, inducing the emergence of polar nanoregions (PNRs), which enhances the ESP of the ceramics. The BNLST-0.2KN ceramic demonstrates a high recovered energy density ( W rec ∼ 3.66 J/cm 3 ) and efficiency (η ∼ 85.8%) under a low electric field of 210 kV/cm. Meantime, it exhibits a large current density ( C D ∼ 831.74 A/cm 2 ), high power density ( P D ∼ 78.86 MW/cm 3 ), and fast discharge rate ( t 0.9 ∼ 0.1 μs), along with good temperature stability and excellent fatigue stability. These properties make the BNLST-0.2KN ceramic a promising candidate for energy storage applications in low electric fields.