In recent years, sodium bismuth titanate (Bi_0.5Na_0.5TiO₃, BNT) -based relaxor ferroelectrics have attracted more and more attention for energy storage applications owing to their high power density, large saturated polarization (P_S)/maximum polarization (P_max) as well as meeting the needs of environment-friendly society. However, the recoverable energy storage density (W_rec) and energy storage efficiency (η) of most BNT-based relaxor ferroelectric ceramics are lower than 3.5 ​J ​cm⁻³ and/or 80%, respectively, in recently. In this work, the relaxor ferroelectric ceramics of 0.75Bi_(0.5+x)Na_(0.5-x)TiO₃-0.25SrTiO₃ (BNST-x) were constructed via A-site defect engineering and prepared by tape-casting method. It is worth noting that an ultrahigh W_rec of 5.63 ​J ​cm⁻³ together with outstanding η of 94% can be achieved simultaneously at a relative high electric field of 535 ​kV ​cm⁻¹ with the composition of BNST-0.08, Meanwhile, for BNST-0.08 ceramic, the η is higher than 90% and the variation of W_rec is less than ±2% and ±5% within the frequency range of 1–100 ​Hz and temperature range of 30–130 ​°C, respectively. The W_rec is always higher than 3 ​J ​cm⁻³ and did not deteriorate significantly after 10⁴ fatigue cycles. In addition, the BNST-0.08 ceramic also possesses ultrafast discharge speed (t_0.9, less than 125 ​ns) and ultrahigh power density (P_D, higher than 147 ​MW ​cm⁻³) within the temperature range of 30–130 ​°C at 300 ​kV ​cm⁻¹. Therefore, the BNST-0.08 ceramic is promising candidate environment-friendly materials for advanced pulsed power capacitor applications and the energy storage properties of BNT-based relaxor ferroelectrics can be enhanced significantly via A-site defect engineering.

近年来，钛酸铋钠（Bi _0.5 Na _0.5 TiO ₃，BNT）基弛豫铁电材料由于其高功率密度，大饱和极化强度（_PS）/最大极化强度（P）而在储能应用中受到越来越多的关注。_最高）以及满足环境友好型社会的需求。然而，最近大多数基于BNT的弛豫铁电陶瓷的可恢复储能密度（W _rec）和储能效率（η）分别低于3.5 J cm ^-3和/或80％。在这项工作中，0.75Bi _{（0.5 + x）} Na _（0.5-x） TiO的弛豫铁电陶瓷通过A位缺陷工程构造了_3- -0.25SrTiO ₃（BNST-x），并通过流延法制备。值得注意的是，在BNST-0.08的相对高电场535 kV cm ^-1下，可以同时获得5.63 J·cm ^-3的超高W _rec和94％的出色η ，同时，对于BNST-0.08陶瓷，在1-100 Hz的频率范围和30-130°的温度范围内，η高于90％，W _rec的变化小于±2％和±5％ C分别。W _rec总是高于3 J cm ^-3且在10 ⁴之后并没有明显恶化疲劳周期。此外，BNST-0.08陶瓷还具有超快排出速度（吨_0.9，小于125纳秒）和超高功率密度（P _d，高于147兆瓦厘米^-3的温度范围30-130内） 300 kV cm ^-1下的°C 。因此，BNST-0.08陶瓷有望成为先进脉冲功率电容器应用中的候选环保材料，并且通过A站点缺陷工程可以显着提高BNT基弛豫铁电体的储能性能。