Preparation of a novel cross‐linked polyetherimide with enhanced breakdown strength and high‐temperature energy storage performance

Abstract 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 owing rapidly decreasing discharged density ( U d ) charge‐discharge efficiency η ). Herein, novel PEI cross‐linked networks was firstly prepared by utilising 2,4,6‐Triaminopyrimidine (TAP) cross‐linker. The results showed that breakdown strength of (c‐PEI) 2 wt% TAP increased 399.4 MV/m, showing an increment 23.3% comparison non‐cross‐linked PEI. Additionally, restrained polarisation loss relaxation networks, c‐PEI gradually decreased increasing content TAP. Of particular significance exhibiting improved temperature. maximum 2.53 J/cm 3 150°C, 24.8% higher than (2.11 150°C). This research provides innovative strategy achieve