Enhanced dielectric property and energy-storage performance of polyetherimide composite with TiO2@BaTiO3 core–shell particles

The development of polymer-based dielectric materials with simultaneously enhanced dielectric permittivity and energy-storage capability is of great importance for next-generation electronic and electrical devices. In this work, polyetherimide (PEI) composite films have developed by incorporating in-situ synthesized TiO 2 @BaTiO 3 (BTO) core–shell functional nanobars to achieve enhanced interfacial polarization. The TiO 2 @BTO particles are prepared through a sequential hydrothermal route, in which TiO 2 serves as the template for the growth of BTO shell. Owing to the one-dimensional core–shell architecture, the TiO 2 @BTO/PEI composite with enlarged interfacial area demonstrates the regulation of the local electric field in the polymer matrix. The incorporation of TiO 2 @BTO particles significantly enhances the dielectric constant, polarization response, and energy-storage performance of composite. The 0.5 wt% composite exhibits the outstanding overall performance, showing a favorable balance among dielectric enhancement, electrical reliability, and energy-storage behavior, e.g. energy density of 12.3 J cm −3 and charge-discharge efficiency of 85% at 400 MV m −1 . The improved energy storage property is mainly attributed to the synergistic effects of the highly polarizable BTO shell and the Maxwell–Wagner–Sillars interfacial polarization. The rational design of one-dimensional core–shell nanofillers is an effective strategy for developing high-performance PEI-based dielectric composites for capacitive energy-storage applications.