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 polymer dielectrics owing to the rapidly decreasing discharged energy density (Ud) 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 Ud and η at high temperature. The maximum Ud 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 Ud and η at high temperature.

Simultaneous Inhibition of Conduction Loss and Enhancement of Polarization Intensity of Polyetherimide Dielectrics for High-Temperature Capacitive Energy Storage

“…Additionally, PI dielectrics cannot be directly melt-processed and remelted due to their intrinsic thermoset feature, which is contradictory to the environmentally friendly requirement. Employing thermoplastic polyetherimide (PEI) dielectric with a considerable amount of flexible ether groups in the backbone can effectively remedy the aforementioned shortcomings of PI dielectrics. − However, the commercially available PEI dielectric (Ultem 1000) also undergoes a distinct increase in the conduction loss at increased temperatures.…”

“…The discharged energy density of AlN/PEI composites (4.79 J/cm 3 ) at 150 °C in this contribution exceeds most of the previously reported results for PEI composites (Figure S6). ,,− ,− This suggests that the metal nitrides are a kind of promising inorganic filler for the enhancement of capacitive energy storage performance in the polymer dielectrics.…”