Polymer dielectrics with excellent energy storage performance at high temperature are urgently needed in advanced applications, such as hybrid electric vehicles, smart grid and pulsed power sources. Polyetherimide (PEI), which is supposed to be the most promising candidate among polymer dielectric materials, displays a limitation for high-temperature polymer dielectrics owing to the rapidly decreasing discharged energy density (U_d) and charge-discharge efficiency (η). Herein, a novel PEI with cross-linked networks was firstly prepared by utilising 2,4,6-Triaminopyrimidine (TAP) as a cross-linker. The results showed that the breakdown strength of the cross-linked PEI (c-PEI) with 2 wt% TAP increased to 399.4 MV/m, showing an increment of 23.3% in comparison with non-cross-linked PEI. Additionally, owing to the restrained polarisation loss and relaxation loss by cross-linked networks, the dielectric loss of c-PEI dielectric gradually decreased with the increasing content of TAP. Of particular significance was the c-PEI dielectrics exhibiting improved U_d and η at high temperature. The maximum U_d of c-PEI with 2 wt% TAP was 2.53 J/cm³ at 150°C, which was 24.8% higher than non-cross-linked PEI (2.11 J/cm³ at 150°C). This research provides an innovative strategy to achieve novel PEI dielectrics with improved U_d and η at high temperature.

中文翻译：

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一种具有增强击穿强度和高温储能性能的新型交联聚醚酰亚胺的制备

混合动力电动汽车、智能电网和脉冲电源等先进应用迫切需要在高温下具有优异储能性能的聚合物电介质。聚醚酰亚胺（PEI）被认为是聚合物介电材料中最有前途的候选者，但由于放电能量密度（ U _d）和充放电效率（η ）快速下降，在高温聚合物介电材料中表现出局限性。）。在此，首先利用2,4,6-三氨基嘧啶（TAP）作为交联剂制备了具有交联网络的新型PEI。结果表明，添加2 wt% TAP的交联PEI（c-PEI）的击穿强度增加至399.4 MV/m，与非交联PEI相比增加了23.3%。此外，由于交联网络抑制了极化损耗和弛豫损耗，c-PEI电介质的介电损耗随着TAP含量的增加而逐渐降低。特别重要的是 c-PEI 电介质在高温下表现出改进的U _d和η 。含有 2 wt% TAP 的 c-PEI 的最大U _{d为 2.53 J/cm} ³150°C 时，比非交联 PEI（150°C 时2.11 J/cm ^{3 ）高 24.8%。}这项研究提供了一种创新策略，可实现高温下U _d和η得到改善的新型 PEI 电介质。