Superior Thermal Stability and Energy Storage Properties of (1-x)(Bi,Na)0.6(Ba,Sr)0.4TiO3-xZnTa2O6 Lead-free Ceramic

• An excellent thermal stability following X7R specification compared with other typical BNT-based ceramics. • ZT5 ceramic possesses the high W rec of 3.06 J/cm 3 and high η of 92.91%. • A fast discharge speed t 0.9 ~ 170 ns and high P D ~ 60.46 MW/cm 3 were achieved. • The energy density is degraded around 3% over 100000 cycles. It is challengeable to winden the operating temperature and optimize the energy storage properties of ceramic capacitors in power system applications. Here, the lead-free (1-x) Na 0.3 Bi 0.3 Ba 0.04 Sr 0.36 TiO 3 -xZnTa 2 O 6 (BNBST-xZT) ceramics were designed. The introduction of ZT into BNBST reduced the temperature of permittivity peak of BNBST ceramic, which guaranteed the superior thermal stability following X7R specification. Due to the compositional disorder and structural distortion, the ferroelectric order of BNBST was broken, mitigating polarization saturation. The high recoverable energy density ( W rec = 3.06 J/cm 3 ) with high efficiency ( η = 92.91%) was achieved under 270 kV/cm. The fast discharge speed ( t 0.9 ~ 170 ns), large power density ( P D = 60.46 MW/cm 3 ), thermal stability, and superior cycle stability were evaluated to illustrate its promising practical prospect using in pulsed power capacitor devices.