High energy density and high thermal stability of energy-storage properties (ESP) under low electric fields are extremely crucial for the application of dielectric ceramics in miniaturized equipment. In present work, we use a composition-optimization approach to break the long-range ferroelectric order and modulate polar nanoregions (PNRs) in the local structure of (1-x)[0.7(Na_0.5Bi_0.5)TiO₃-0.3(Sr_0.7Bi_0.2)TiO₃]-xBi(Mg_0.5Ti_0.5)O₃ system. The large P_max value is maintained due to the existence of Bi ions in both the matrix and dopants. As a result, a high W_rec of 3.03 J/cm³ together with a moderate η of 79.5 % was obtained in x = 0.05 sample at a low electric field of 200 kV/cm. Meanwhile, the high W_rec (2.41–2.52 J/cm³) and excellent thermal stability of ESP (W_rec varying less than 4.3 % and η > 90 %) from 50 °C to 200 °C at 150 kV/cm were also observed. The current system will be a promising candidate in energy-storage capacitor applications under low-fields and high-temperature.

在低电场下，高能量密度和高能量存储特性（ESP）的热稳定性对于在小型设备中应用介电陶瓷至关重要。在目前的工作中，我们使用一种成分优化方法来打破远距离铁电有序并调制（1-x）[0.7（Na _0.5 Bi _0.5）TiO ₃ -0.3（Sr ）的局部结构中的极性纳米区域（PNR）。_0.7 Bi _0.2）TiO ₃ ] -xBi（Mg _0.5 Ti _0.5）O ₃系。由于在基质和掺杂剂中都存在Bi离子，因此维持了较大的P _max值。结果，高W _rec在200 kV / cm的低电场下，在x = 0.05的样品中获得了3.03 J / cm ³的摩尔分数和79.5％的中等η。同时，在150 kV / cm的温度下，从50°C到200°C ，ESP的高W _rec（2.41-2.52 J / cm ³）和优异的热稳定性（W _rec变化小于4.3％，η> 90％）观测到的。当前系统将在低场和高温下的储能电容器应用中成为有希望的候选者。