Electrostatic energy storage performances of La(Ni _2/3 Ta _1/3 )O ₃ ‐modified Na _0.5 Bi _0.5 TiO ₃ lead‐free ceramics

Abstract Ceramic capacitors with high electrostatic energy storage performances have captured much research interest in latest years. Sodium bismuth titanate (Na 0.5 Bi 0.5 TiO 3 )‐based ferroelectric ceramics show great potential due to their environment‐friendly composition, high polarization, and excellent relaxor properties. However, the nonergodic relaxor state of Na 0.5 Bi 0.5 TiO 3 ‐based ceramics hampers the decrement of remanent polarization, leading to poor energy storage performance. Herein, the (1 − x )Na 0.5 Bi 0.5 TiO 3 – x La(Ni 2/3 Ta 1/3 )O 3 ceramics were designed to generate the transformation between nonergodic and ergodic relaxor state. As a result, the ceramics exhibit improved dielectric relaxation, slim polarization–electric field loops, and flattened current–electric field curves due to highly dynamic polar nanoregions. Particularly, the 0.85Na 0.5 Bi 0.5 TiO 3 –0.15La(Ni 2/3 Ta 1/3 )O 3 ceramics show large breakdown electric field E b (345 kV/cm), high recoverable energy density W rec (3.6 J/cm 3 ), and efficiency η (80.6%), revealing potential applications in electrostatic energy storage.