Ultrahigh Energy Efficiency and Large Discharge Energy Density in Flexible Dielectric Nanocomposites with Pb0.97La0.02(Zr0.5SnxTi0.5-x)O3 Antiferroelectric Nanofillers

High Energy Storage Performance of PMMA Nanocomposites Utilizing Hierarchically Structured Nanowires Based on Interface Engineering

To overcome the inherent high hysteresis loss of ferroelectric polymer-based nanocomposites, non-ferroelectric linear dielectric poly(methyl methacrylate) (PMMA) is adopted as the polymer matrix for high discharge efficiency. At the same time, slender ferroelectric BaTiO₃ nanowires (BT NWs) with a high dielectric constant are selected as the nanofiller for high energy density. To avoid the agglomeration of BT NWs and enhance the strength of interfaces, dopamine is used as organic coatings to tailor the interface. The BT@dopa NWs/PMMA nanocomposites exhibit excellent interface compatibility between the BT NWs and PMMA matrix and a very good microstructure uniformity. Based on this, hierarchically structured BT@SiO₂@dopa NWs are designed and prepared to overcome the uneven electric field distribution at the interface, resulting from the dielectric constant mismatch. The discharged energy density (U_e) can be largely enhanced from 3.76 J/cm³ for pure PMMA films to 11.78 J/cm³ for PMMA-based nanocomposites by incorporating 5.0 wt % BT@SiO₂@dopa NWs. In addition, a high discharging efficiency (η) of 91% is obtained simultaneously in the nanocomposites. Both experimental and theoretical simulations demonstrate that the double core-shell structure nanowire fillers can effectively alleviate the local field distortion, inhibit leakage current, and suppress remnant electric displacement, leading to the high U_e and η. These findings are significant in facilitating the development of high-performance film dielectric capacitor materials using PMMA-based nanocomposites toward high energy storage density.

Three-dimensionally ordered macroporous BaTiO3 framework-reinforced polymer composites with improved dielectric properties

Polymer composites with high dielectric constants are highly desired in advanced electronic devices and the modern electrical industry. The dielectric constant of three-dimensional filler-reinforced polymer composites is usually enhanced at the expense of flexibility. Herein, barium titanate inverse opals (BT_IOs) that have three-dimensionally ordered and interconnected macropores are prepared and introduced into a poly (vinylidene fluoride) (PVDF) matrix to tailor their dielectric properties. The composite films with 30 wt% BT_IOs exhibit a dielectric constant of 18.8 at 1 kHz, showing an enhancement of 154% and 35% compared with that of pristine PVDF and their corresponding composites reinforced with barium titanate nanoparticles, respectively. Meanwhile, the dielectric loss is suppressed at 0.088. The BT_IOs/PVDF composite films also maintain good flexibility and can be freely bent. This design of three-dimensionally ordered macroporous filler-reinforced polymer composites with improved dielectric constants and good flexibility presents promising applications of dielectric materials in flexible electronics.