▎ 摘　　要

Dielectric polymer composites as energy storage components greatly promote the development of highperformance power electronic devices. However, the failure under high voltage and high temperature is still the main problem to be solved. In this work, a non-covalently modified graphene@poly(ionic liquid) (RGO@PIL) nanohybrid has been elaborately designed. The It-It conjugated structure of the nanohybrid prevents the filler from overlapping and improves its dispersion, thus improving the breakdown strength by effectively extending the breakdown path. The double polymer shell structure formed after the introduction of poly(ionic liquid) not only enhances the interfacial polarization effect but also significantly transfers heat evenly within the nanocomposites avoiding failure at high temperatures. At the frequency of 1 kHz and at 200 degrees C, the permittivity of the nanocomposite film reaches 35.51, with a high breakdown strength of 122.96 kV/mm. This work demonstrates a promising strategy to manufacture the electronic circuit equipment materials for applications under extreme environments.