Abstract Dielectric composites with a high dielectric constant and electric breakdown strength are highly desired for the excellent energy storage behavior of the microelectronic and electric power systems. Sandwich-structured composites with an insulating layer can provide a pathway to improve the dielectric and energy storage performance, and in general, the fillers design and volume control of the insulating layer are very important. Herein, we present a novel designed sandwich-structured aluminum nitride/potassium niobate/poly(vinylidene fluoride) (AlN/KNbO3/PVDF) nanocomposites by the solution-casting and hot-pressing process. The effect of the introduction of an insulating phase AlN in the two outer layers and a different KNbO3 volume fraction in the middle layer on the dielectric properties and energy storage behavior of the sandwich-structured composites were investigated in detail. The results demonstrate that dielectric constant, electric breakdown strength, energy storage density and discharged efficiency of the AlN/KNbO3/PVDF sandwich-structured composites are significantly enhanced. Moreover, a high energy density of 10.54 J/cm3 and a superior discharged energy efficiency of 70% at the electric breakdown strength of 337 MV/m are achieved in the sandwich-structured nanocomposites with 1 vol% KNbO3 in middle layer and with 1 vol% AlN in the outer layers, which are much higher than the conventional single-layered KNbO3/PVDF composites. It is indicated that the introduction of insulating layers in sandwich-structure composites can improve the electric breakdown strength and discharge efficiency, as confirmed by analyzing results of the finite element simulations. This work may provide an effective approach to develop excellent performance dielectric composites for electrical energy storage applications.

中文翻译：

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通过引入 AlN/PVDF 绝缘层显着提高 AlN/KNbO3/PVDF 夹层结构复合材料的介电和储能性能

摘要 具有高介电常数和电击穿强度的介电复合材料因其优异的微电子和电力系统储能性能而备受青睐。具有绝缘层的夹心结构复合材料可以提供提高介电和储能性能的途径，通常绝缘层的填料设计和体积控制非常重要。在此，我们通过溶液浇铸和热压工艺提出了一种新型设计的三明治结构氮化铝/铌酸钾/聚偏二氟乙烯（AlN/KNbO3/PVDF）纳米复合材料。详细研究了在两个外层中引入绝缘相 AlN 和在中间层中引入不同的 KNbO3 体积分数对夹层结构复合材料的介电性能和储能行为的影响。结果表明，AlN/KNbO3/PVDF夹层结构复合材料的介电常数、电击穿强度、储能密度和放电效率均显着提高。此外，夹层结构纳米复合材料具有 10.54 J/cm3 的高能量密度和 70% 的优异放电能量效率，在 337 MV/m 的电击穿强度下，中间层含有 1 vol% KNbO3，1 vol外层中的 AlN 百分比，远高于传统的单层 KNbO3/PVDF 复合材料。有限元模拟分析结果表明，在夹层结构复合材料中引入绝缘层可以提高电击穿强度和放电效率。这项工作可能为开发用于电能存储应用的性能优异的介电复合材料提供一种有效的方法。