Poly(ether imide) Nanocomposites with BaTiO<sub>3</sub>@TiO<sub>2</sub>@SiO<sub>2</sub> or BaTiO<sub>3</sub>@SiO<sub>2</sub>@TiO<sub>2</sub> Fillers Improve Energy Storage Capacity and Dielectric Thermal Stability
Peiyuan Zuo, Junhao Jiang, Ruoqi Wang, Donglin Chen, Jingyu Lin, Yi Chen, Xinhua Wang, Qixin Zhuang
Abstract
The core–shell structures have been widely accepted as an effective way to adjust the dielectric properties of polymer-based nanocomposites. However, there rarely exist systematic studies, considering the core–double-shell sequence comparison (gradient or antigradient permittivity) on comprehensive dielectric and thermal stability properties for linear PEI polymer-based nanocomposites. To fill this gap, we herein successfully fabricated a series of BaTiO 3 @TiO 2 @SiO 2 /PEI and BaTiO 3 @SiO 2 @TiO 2 /PEI nanocomposites, the energy storage density of which can reach 5 and 5.41 J/cm 3 with 10 vol % of filler, respectively. The resulting energy storage capacities are 2.7 and 2.85 times that for pure PEI. The BaTiO 3 @TiO 2 @SiO 2 /PEI nanocomposites possess excellent breakdown strength (∼470 MV/m) and low dielectric loss (∼0.008) with a 5 vol % of filler. Both the core–double-shelled nanocomposites exhibit excellent dielectric stability over a wide temperature range from RT to 150 °C compared to BaTiO 3 /PEI and BaTiO 3 @SiO 2 /PEI. The electric field simulation and DFT calculation results are highly consistent with the analysis of experimental data. This innovative work lays a solid foundation for further investigation on core–double-shell-structured dielectrics.