Electrostatic capacitors with excellent energy storage capacity and great thermal stability have become the researching focus. However, high-energy–density electrostatic capacitors are restricted through insurmountable drawbacks of low charge–discharge efficiency under high temperature/voltage working conditions. Herein, polyetherimide (PEI) nanocomposite films contains with two-dimensional boron nitride nanosheets (h-BNNS) are fabricated by solution casting method. Consequently, h-BNNS/PEI nanocomposite films exhibit tremendously breakdown strength (E_b ~ 700 MV/m), accompany with a record discharge efficiency (η ~ 93.6%) at room temperature with filler content of 4 vol%. The simulations and experiments results suggest that the h-BNNS loading into the PEI matrix could efficiently improve the high-temperature endurance. Particularly, the composites films exhibit superior comprehensive capacitive properties, e.g., discharged energy density of 3.43 J/cm³ along with η of 90.1% under 500 MV/m and 150 °C. Therefore, these characteristics render our polymer film an ideal material candidate for high-performance dielectric applications at evaluated temperature.

具有优异的储能能力和良好的热稳定性的静电电容器已成为研究的重点。但是，高能量密度的静电电容由于在高温/高压工作条件下充放电效率低的无法克服的缺点而受到限制。在此，通过溶液流延法制造包含二维氮化硼纳米片（h-BNNS）的聚醚酰亚胺（PEI）纳米复合膜。因此，H-BNNS / PEI纳米复合膜表现出极大击穿强度（Ë _b  〜700兆伏/米），具有记录放电效率陪（η 约93.6％）在室温下，填料含量为4 vol％。仿真和实验结果表明，h-BNNS加载到PEI矩阵中可以有效地提高高温耐受性。特别地，复合膜表现出优异的综合电容特性，例如，在500MV / m和150℃下的放电能量密度为3.43J / cm ³，η为90.1％。因此，这些特性使我们的聚合物薄膜成为评估温度下高性能介电应用的理想材料。