Enhanced dielectric performance with high-temperature stability by interface-modulation of the core–shell structured imide-polymer@BT nanohybrids in PEI-based nanocomposites

Abstract

Ceramic–polymer nanocomposites with increased dielectric constant are desired to fabricate advanced film capacitors. However, the introduced ceramics usually lead to a decreased breakdown strength due to their extremely different properties from polymers, thus restricting the substantial improvement of energy density. Herein, a core–shell structured imide-polymer@barium titanate (BT) is designed, and a modulation strategy optimizing the dielectric behavior at the interface of BT-polyetherimide (PEI) by introducing phthalocyanine and –CF₃ groups to enhance the dielectric response and construct energy traps is proposed to manufacture a high-performance polymeric dielectric. The interface between BT and PEI is reinforced owing to the electrostatic interaction between the polymer chains of the PEI matrix and the imide-polymer shell. Compared with BT-PEI, the modified BT-PEI nanocomposites exhibit improved comprehensive dielectric properties and breakdown strength. The prepared composite possesses the highest discharge energy density of 3.04 J cm⁻³ with a charge–discharge efficiency of 89.25%. Moreover, the dielectric properties of the prepared composites possess excellent thermal stability from 20 °C to 150 °C. This work provides a promising strategy to develop polymeric dielectrics for high-temperature applications.