Polymer dielectrics are required to maintain high energy density at elevated temperatures for advanced power and electronic systems. Herein, we report a novel solution-processed core-shell structured polyimide (PI) nanocomposite with moderate dielectric constant HfO core and wide-bandgap AlO shell, effectively addressing the typical trade-off between dielectric constant and breakdown strength in dielectric nanocomposites predominant at elevated temperatures. The formation of improved dielectrically matching interfaces by the rationally designed dielectric constant gradient from core-shell-matrix remarkably mitigates the distortion of the electric field around the interfaces, resulting in a high breakdown strength. Wide band gap AlO shell also introduces deeper traps to impede the conduction loss. The validity of AlO shell has been proved via experiments and simulations. Accordingly, HfO@AlO/PI nanocomposite exhibits an excellent charge-discharge efficiency of 91.7 % at 300 MV/m and a maximum discharged energy density of 2.94 J/cm at 150 °C, demonstrating its potential for high-temperature energy storage.

中文翻译：

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通过合理设计的核壳结构纳米填料，聚合物纳米复合材料在高温下同时提高介电常数和击穿强度


先进的电力和电子系统需要聚合物电介质在高温下保持高能量密度。在此，我们报告了一种新型溶液加工的核壳结构聚酰亚胺（PI）纳米复合材料，具有中等介电常数 HfO 核和宽带隙 Al2O 壳，有效解决了介电纳米复合材料介电常数和击穿强度之间的典型权衡问题。温度。通过合理设计的核-壳-基体介电常数梯度形成改进的介电匹配界面，显着减轻了界面周围电场的畸变，从而产生高击穿强度。宽带隙 Al2O3 壳还引入了更深的陷阱来阻止传导损耗。通过实验和模拟证明了Al2O3壳的有效性。因此，HfO@Al2O/PI纳米复合材料在300 MV/m时表现出优异的充放电效率，为91.7%，在150℃时最大放电能量密度为2.94 J/cm，展现了其高温储能的潜力。