Core-double-shell structured nanocomposite dielectrics with high permittivity and low loss for electric energy storage

Nanocomposite dielectrics with high permittivity and low dielectric loss have potential applications in energy storage devices. In this work, the unique core-double-shell barium titanate (BaTiO₃) nanocomposite dielectrics were successfully prepared by an in situ polymerization technique, in which BaTiO₃ nanoparticles were used as the core, and the two shells are hyperbranched aromatic polyamide (HBP) and poly(methyl methacrylate) (PMMA) from the inside to outside. The dielectric response and electric displacement-electric field loops of the nanocomposites were measured by using broadband dielectric spectroscopy and ferroelectric polarization tester. The results show that, compared with the nanocomposites prepared by conventional methods (i.e., solution blending), the core-double-shell structured nanocomposites have higher dielectric constant, lower dielectric loss and higher energy density. Our study suggests that one can tune the dielectric and energy storage properties of nanocomposites dielectrics by using the multi-shell strategy.