Abstract Polymer dielectrics are preferred materials for high-energy-density capacitive energy storage. In particular, high-temperature dielectrics that can withstand harsh conditions, e.g., ≥150 °C, is of crucial importance for advanced electronics and electrical power systems. Herein, high-temperature dielectric polymer composites composed of polyetherimide (PEI) matrix and hafnium oxide (HfO2) nanoparticles are presented. It is found that the incorporation of HfO2 with a moderate dielectric constant and a wide bandgap improves the dielectric constant and simultaneously reduces the high-field leakage current density of the PEI nanocomposites. As a result, the PEI/HfO2 composites exhibit superior energy storage performance to the current high-temperature engineering polymers at elevated temperatures. Specifically, the nanocomposite with 3 vol% HfO2 displays a discharged energy density of 2.82 J/cm3 at 150 °C, which is 77% higher than neat PEI. This work demonstrates the effectiveness of incorporation of the nanofiller with a medium dielectric constant into the polymer on the improvement of high-temperature capacitive properties of the polymer composites.

中文翻译：

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用于高温薄膜电容器的含 HfO2 纳米颗粒的聚合物复合材料的介电性能大大增强

摘要 聚合物电介质是高能量密度电容储能的首选材料。特别是，能够承受恶劣条件（例如≥150°C）的高温电介质对于先进的电子和电力系统至关重要。本文介绍了由聚醚酰亚胺 (PEI) 基体和氧化铪 (HfO2) 纳米颗粒组成的高温介电聚合物复合材料。发现具有中等介电常数和宽带隙的 HfO2 的掺入提高了介电常数，同时降低了 PEI 纳米复合材料的高场漏电流密度。因此，PEI/HfO2 复合材料在高温下表现出优于当前高温工程聚合物的储能性能。具体来说，含有 3 vol% HfO2 的纳米复合材料在 150 °C 下的放电能量密度为 2.82 J/cm3，比纯 PEI 高 77%。这项工作证明了将具有中等介电常数的纳米填料掺入聚合物中对提高聚合物复合材料的高温电容性能的有效性。