Dielectric capacitors are in urgent need of miniaturized and lightweight products. The new lead-free NaNbO₃-based ferroelectric ceramic material is a good choice owing to its high energy storage density, superior charge/discharge performance and decent frequency/temperature stability. In this work, a novel lead-free relaxor ferroelectric ceramic, (1-x)NaNbO₃-xBa(Mg_1/3Nb_2/3)O₃ [(1-x)NN-xBMN, x = 0.18, 0.20, 0.22 and 0.24], was designed and prepared via a local random field strategy. The impedance analysis demonstrates that the introduction of BMN could enhance the insulation ability and breakdown strength of the (1-x)NN-xBMN ceramic. Finally, the excellent energy storage performances with simultaneously ultrahigh energy storage density (W_st～4.04 J/cm³), recoverable energy storage density (W_rec～3.51 J/cm³), efficiency (η～87 %) and fatigue endurance (number of cycles: 5000) are obtained in the 0.78NN-0.22BMN ceramic. In addition, excellent frequency (1～100 Hz) and temperature stability (20～140 °C) can also be observed in the 0.78NN-0.22BMN ceramic. It is crucial that the ceramic shows extremely short charge-discharge time (t_0.9～45 ns), tremendous current density (C_D～680 A/cm²), giant power density (P_D～47.6 MW/cm³) and excellent temperature stability (30～150 °C). These results indicate that 0.78NN-0.22BMN ceramic is a promising dielectric capacitor material.

介电电容器迫切需要小型化和轻量化的产品。新型无铅NaNbO ₃基铁电陶瓷材料因其高的储能密度，出色的充电/放电性能以及良好的频率/温度稳定性而成为了不错的选择。在这项工作中，一种新型的无铅弛豫铁电陶瓷（1- x）NaNbO ₃ - x Ba（Mg _1/3 Nb _2/3）O ₃ [（1- x）NN- x BMN，x= 0.18、0.20、0.22和0.24]是通过局部随机场策略设计和制备的。阻抗分析表明，引入BMN可以增强（1- x）NN- x BMN陶瓷的绝缘能力和击穿强度。最后，优良的能量储存性能同时与超高能量存储密度（w ^ _ST〜4.04焦耳/厘米³），可回收能量存储密度（w ^ _REC〜3.51焦耳/厘米³），效率（η在0.78NN-0.22BMN陶瓷中获得了约87％的耐疲劳性（循环数：5000）。另外，在0.78NN-0.22BMN陶瓷中也可以观察到极好的频率（1〜100 Hz）和温度稳定性（20〜140°C）。至关重要的是，该陶瓷显示极短的充放电时间（吨_0.9〜45纳秒），巨大电流密度（ç _d〜680 A /厘米²），巨功率密度（P _d〜47.6兆瓦/厘米³）和优异的温度稳定性（30〜150°C）。这些结果表明0.78NN-0.22BMN陶瓷是一种有前途的介电电容器材料。