Significant Improvements in Dielectric Constant and Energy Density of Ferroelectric Polymer Nanocomposites Enabled by Ultralow Contents of Nanofillers

Abstract

Polymer dielectrics with excellent processability and high breakdown strength (Eb) enable the development of high‐energy‐density capacitors. Although the improvement of dielectric constant (K) of polymer dielectric has been realized by adding high‐K inorganic fillers with high contents (>10 vol%), this approach faces significant challenges in scalable film processing. Here, the incorporation of ultralow ratios (<1 vol%) of low‐K Cd1−xZnxSe1−ySy nanodots into a ferroelectric polymer is reported. The polymer composites exhibit substantial and concurrent increase in both K and Eb, yielding a discharged energy density of 26.0 J cm−3, outperforming the current dielectric polymers and nanocomposites measured at ≤600 MV m−1. The observed unconventional dielectric enhancement is attributed to the structural changes induced by the nanodot fillers, including transformation of polymer chain conformation and induced interfacial dipoles, which have been confirmed by density function theory calculations. The dielectric model established in this work addresses the limitations of the current volume‐average models on the polymer composites with low filler contents and gives excellent agreement to the experimental results. This work provides a new experimental route to scalable high‐energy‐density polymer dielectrics and also advances the fundamental understanding of the dielectric behavior of polymer nanocomposites at atomistic scales.

Ultrahigh Energy Density in Continuously Gradient‐Structured All‐Organic Dielectric Polymer Films

“…Figure 4d presents a comparison of the U d and η values of our gradient polymer film with those of recently reported high-energy-density polymer-based dielectrics including polymer nanocomposites. [11,[21][22][23]43,50,52,53,[61][62][63][64] The comparison demonstrates the superiority of the energy storage performances achieved with nonlinear gradient polymer films. It is known that ferroelectric PVDF-based polymers usually suffer from a low η (below 80%), limiting their practical application in capacitor applications; [53,65] therefore, concurrently high U d and η are desirable.…”

Recent progress on dielectric polymers and composites for capacitive energy storage

“…Crosslinked PVDF [52] 2.0 wt.% BaTiO 3 -DPA 11.6 (100 Hz) 0.135 (100 Hz) 242 2.9 @ 275 MV/m 75 PVDF [53] 4 vol.% modified BaTiO 3 ~11.5 ~0.02 517 11.27 @ 520 MV/m 60 PVDF [54] 50 vol.% modified BaTiO 3 ~28 0.038 328 9.89 60 P(VDF-HFP) [79] 10 vol.% SiO 2 986.2 27.1 0.03 390 5.1 P(VDF-HFP) [128] 0.82 vol.% CdSe/Cd 1D nanofillers PVDF [51] 2.1 vol.% BaTiO 3 -PDA ~11 <0.04 340.4 7.03 @ 330 MV/m P(VDF-HFP) [58] 5 vol.% BaTiO 3 -PDA ~12 ~0.05 ~470 12.87 @ 480 MV/m ~55 P(VDF-CTFE) [59] 3 vol.% Z-aligned BaTiO 3 ~16 271.9 10.8 @ 240 MV/m 61.4…”

Low‐content metal‐organic framework enhanced interface effect to improve the insulation properties of polyimide‐based composite films

“…Li et al 9 constructed the interface bonding region by modifying the surface of nanofillers and proposed the multi‐regions model. Wang et al 10 established the dielectric model based on the multi‐core model and density functional theory to explore the limitations of the volume average model of low content composites, and so on. In addition to establish the model, researchers also attempted other strategies to explore the mechanisms that the interface enhances the insulation properties.…”