Sandwich-structured relaxor ferroelectric nanocomposite incorporated with core-shell fillers for outstanding-energy-storage capacitor application

Significance reduction in characteristic dimension and weight of energy conversion system is urgently needed for developing outstanding-energy-density dielectric materials. For conventional single-layer configuration, huge enhancments in dielectric constant (K) was achieved in polymer nanocomposite system by the introduction of high-K fillers at the expense of the breakdown strength (Eb). Herein, we reported that the crafting of core-shell structured BT@TP NPs and BN@TP NSs was used as the nanofillers to achieve a sandwich-structured nanocomposite that one high-K layer of BT@TP-TP was sandwiched by two high-Eb layers of BN@TP-TP. In comparison to unmodified BT NPs and BN NSs, the crafting of core-shell BT@TP NPs and BN@TP NSs is beneficial for improving dispersion quality and thus endure high-Eb in the matrix P(VDF-TrFE-CTFE) (TP). The newly designed sandwich-structured polymer nanocomposites are capable of balancing the contradict factors of high-K and high-Eb. In addition, the enhanced interfacial polarization was directly detected by piezoelectric force microscopy, and the formation of electric trees was well displaced by FEA simulation. Outstandingly, the sandwich-structured nanocomposite 3BN@TP-TP/4BT@TP-TP/3BN@TP-TP exhibits a discharged energy density of 10.3 J/cm3 and dicharged-charged efficiency of 71.2 % at a field of 270 MV m−1, which is 5-fold higher than that of commercial BOPP. © 2024 Elsevier B.V.