Excellent energy storage performance for P(VDF-TrFE-CFE) composites by filling core–shell structured inorganic fibers

Abstract

Polymer-based nanocomposites have been attracted much attention due to their great potential application in the fields of electrical engineering and power electronics. It is still one of the most hottest topics to further enhance the capacitive performances of dielectric films. The most common way to increase the energy density of dielectrics is to construct nanocomposites by filling inorganic fillers into polymer matrix. In this study, strontium titanate nanofibers (ST NFs) and P(VDF-TrFE-CFE) (PVTC) are chosen as fillers and polymer matrix, respectively., More importantly, the core–shell structured fillers of ST NFs wrapped with SiO2 (ST@SiO2) have been constructed for improving the interfacial compatibility. The microstructures and electrical energy storage performances of the nanocomposites have been systematically investigated, comparing the impact of fillers with or without SiO2 shell layer. The results show that ST@SiO2/PVTC nanocomposites possess a discharged energy storage density of 7.2 J/cm3 and an efficiency of 70.9% at an ultra-low content of ST@SiO2 (1 vol%) and low electric field of 330 kV/mm. Meanwhile, the maximum recoverable energy storage densities of ST NFs/PVTC (5.5 J/cm3) and pure PVTC (4.7 J/cm3) are inferior to that of ST@SiO2/PVTC nanocomposites. This work provides an effective strategy to enhance the energy storage performances of PVTC polymer films, further confirming the design of core–shell structured fillers is beneficial to obtain excellent capacitive performances at a relative low electric field.