Relaxor ferroelectric (Bi 0.5 Na 0.5 )TiO 3 -based ceramic with remarkable comprehensive energy storage performance under low electric field for capacitor applications

Although high-applied electric field can usually generate high energy storage performance (ESP) for most dielectric materials, the presence of high risk at high electric field and large cost of insulation technology are the main obstacles that critically restrict the actual applications of dielectric ceramics in the energy storage area. Herein, simultaneously realizing high energy storage density ( W rec )/efficiency ( η ) and charge–discharge performance under low working electric fields is proposed in relaxor ferroelectrics via combining the non-ergodic and ergodic relaxor state (NR-ER) and dominated ER features. Based on this idea, a high W rec (2.03 J/cm 3 ) and favorable η (72%), together with excellent frequency dependence (0.5–100 Hz), moderate temperature stability (20–140 °C, and satisfactory fatigue endurance (10 0 –10 5 cycles), can be simultaneously achieved in 0.3[0.955(Bi 0.5 Na 0.5 )TiO 3 –0.045Ba(Al 0.5 Ta 0.5 )O 3 ]–0.7Sr 0.3 (Bi 0.7 Na 0.67 Li 0.03 ) 0.5 TiO 3 (BNT–BAT–0.7SBNLT) ceramic at a low electric field of 200 kV/cm. Moreover, the indicated ceramics also possess great charge–discharge performance at 140 kV/cm, featured by a large power density P D of 46.2 MW/cm 3 , discharge energy density W d of 0.62 J/cm 3 , fast charge-discharge rate t 0.9 of 210 ns, and excellent cycling reliability. Thus, the designed BNT–BAT–0.7SBNLT ceramic possesses superior comprehensive ESP under low electric field, which has broad prospects in practical high-power ceramic capacitors applications.