Controllable Fabrication of Poly(Arylene Ether Nitrile) Dielectrics for Thermal-Resistant Film Capacitors

High-temperature-resistant dielectric films, the heart of energy storage components in film capacitors, are key elements to ensure that the capacitors operate properly in harsh environments. Herein, a kind of flexible thermal-resistant poly(arylene ether nitrile) (TR-PEN) dielectric film with controllable high-temperature resistance is fabricated through post self-crosslinking of PEN at different temperatures for different times. The dielectric films can present extremely high thermal stability (Tg > 370 °C), a long service life at 300 °C (4.5 × 104 min, 95 wt % of the residual weight), and a low temperature coefficient of dielectric constant from 50 to 300 °C (<5 × 10–4 °C–1). The retention of the energy density of TR-PEN350 at 300 °C is higher than 80% compared with that at room temperature. These results indicate that the TR-PEN films can be used over a long term as capacitor films at temperatures up to 300 °C. Besides, the simple and controllable fabrication technique for the TR-PEN can be easily industrialized.