Barium titanate-based energy-storage dielectric ceramics have attracted great attention due to their environmental friendliness and outstanding ferroelectric properties. Here, we demonstrate that a recoverable energy density of 2.51 J cm–3 and a giant energy efficiency of 86.89% can be simultaneously achieved in 0.92BaTiO3-0.08K0.73Bi0.09NbO3 ceramics. In addition, excellent thermal stability (25–100 °C) and superior frequency stability (1–100 Hz) have been obtained under 180 kV cm–1. The first-order reversal curve method and transmission electron microscopy measurement show that the introduction of K0.73Bi0.09NbO3 makes ferroelectric domains to transform into highly dynamic polar nanoregions (PNRs), leading to the concurrently enhanced energy-storage properties by the transition from ferroelectric to relaxor ferroelectric (RFE). Furthermore, it is confirmed by piezoresponse force microscopy that the appearance of PNRs breaks the long-range order to some extent and reduces the stability of the microstructure, which explains the excellent energy-storage performance of RFE ceramics. Therefore, this work has promoted the practical application ability of BaTiO3-based energy-storage dielectric ceramics.

High-performance energy storage dielectrics have been the key to solve energy problems in the context of energy crisis. Designing multilayered structure is an effective approach to breaking the paradox between...

Poly(vinylidene fluoride)-based (PVDF) composites with high discharged energy density (U e ) have been considered as advanced dielectric materials for pulsed power systems and electrical weapon systems. However, further improvement of the U e of PVDF-based composites with higher breakdown strength (E b ) is of utmost importance. Based on the principle of voltage distribution in the multilayer structure, the multilayer structure (five-layer structure) ceramic/polymer composite films consisting of pristine PVDF layers with high breakdown strength and PVDF layers doped with one-dimensional 0.15SrTiO 3 -0.85Na 0.5 Bi 0.5 TiO 3 (1D SNBT) fibers where the two kinds of layers stacked alternately has been designed and fabricated. Accordingly, a series of analyses of the dielectric properties and energy storage performances are presented, and the related results are tentatively explained by finite element simulation. The energy storage characteristics of the composite films are greatly improved due to the newly designed structure. An excellent U e of 20.82 J cm −3 is achieved at an ultrahigh electric field of 640 MV m −1 with the PVDF layers containing 6 vol % SNBT fibers. Therefore, this work provides a new strategy to design and fabricate advanced polymer-based energy storage materials.

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