The significantly enhanced energy storage characteristics of 0.5Ba(Zr _0.2 Ti _0.8 )O ₃ –0.5(Ba _0.7 Ca _0.3 )TiO ₃ nanofibers/PVDF dielectric composites with low doping ratios and large aspect ratio nanofillers.

With the rapid development of next-generation electrical power equipment and microelectronics, there is an urgent demand for dielectric capacitor films which can work efficiently under extreme conditions. However, sharply increased electrical conduction and drastically degrading electric breakdown strength are inevitable at elevated temperatures. Herein, a facile but effective method is proposed to improve high temperature capacitive performance. We report that utilizing an inorganic insulation interlayer can significantly increase the discharge energy density with a high efficiency above 90% at 150 °C, i.e., a discharged energy density of 4.13 J cm⁻³ and an efficiency of >90% measured at 150 °C, which is superior to the state-of-the-art dielectric polymers. Combining the experimental results and computational simulations reveals that the remarkable improvement in energy storage performance at high temperature is attributed to the blocking effects that reduce the leakage current and maintain the breakdown strength. The proposed facile method provides great inspiration for developing polymer dielectric films with high capacitive performance under extreme environments.

Polymer-based dielectric composites have become a hot topic in recent years due to their high-power density and high breakdown strength. However, some disadvantages still exist in some typical monopolymers, which are not conductive to improving the energy storage performances significantly, such as high energy loss of PVDF and low polarization of PMMA. Based on the good compatibility of PMMA and PVDF, this paper proposes a binary polymer blending strategy to improve the polarization and energy storage properties of the dielectric composite. The influences of volume content of PMMA in PVDF and heat treatment temperature during the fabrication process on the microstructure, polarization behaviors and energy storage performances of the PMMA blended PVDF composites (abbreviated as PMMA/PVDF) are systematically investigated. Fortunately, when the heat treatment temperature was 150 °C, the binary blending composite of PMMA/PVDF with a PMMA content of 50 vol% possessed an excellent storage density of 20.1 J cm⁻³ at 570 kV mm⁻¹, and an energy storage efficiency of 63.5%. This study provides an effective method for designing polymer materials with excellent energy storage properties.