Dielectric Properties’ Synergy of Stretched P(VDF-HFP) and P(VDF-HFP)/PMMA Blends Creates Ultrahigh Capacitive Energy Density in All-Organic Dielectric Films

Abstract

Dielectric capacitors with a high energy-storage density and efficiency are urgently required for miniaturization and integration of power electronics and pulsed power system. Herein, single-layered stretched P­(VDF-HFP) with a certain content of poly­(methyl methacrylate) (PMMA) and two kinds of sandwich-structured films are prepared to optimize and compare energy-storage performance. The results revealed that the crystallization transition behavior of stretched P­(VDF-HFP) films contributed to enhance its electric polarization, while the introduction of linear type PMMA resulted in an enhancement of voltage tolerance of stretched films by improving the mechanical properties and suppressing leakage current. What’s more, the effects of crystalline orientations and structure design on the breakdown mechanism of stretched films were revealed by finite element theoretical simulation. As a consequence, the stretched sandwich-structured 0-25-0-S (pure P­(VDF-HFP) serves as the outer layer, and blends represent the middle layer; the digit representing PMMA content in the P­(VDF-HFP)) displayed a high U e of 28.71 J/cm3 and η of 74% under 680 MV/m. This work provides a workable and effective method for developing capacitive films with great energy-storage performance.

Achieving synergistic improvement in dielectric constant and energy storage properties of all-organic liquid crystal molecule/PVDF composites

“…As another strategy, all-organic PVDF-based blends have been embraced and employed because of their good compatibility, similar physicochemical properties and easy machining performance. 24,25 For example, methyl methacrylate–butadiene–styrene copolymer (MBS) 26 and thermoplastic polyurethane (TPU) 27 have been incorporated into PVDF, respectively, and then all-organic PVDF-based composite films were obtained with both improved E b and U d . The results demonstrated that the organic fillers exhibited better compatibility with PVDF than the inorganic fillers and further helped to suppress the breakdown damage at the interface.…”

Dual crosslinked PMMA/BaTiO3 polymer nanocomposite dielectrics for flexible film capacitors

“…20,70,82 When the frequency was increased from 1 kHz to 1 MHz, the change of the dielectric constant of PMMA-BT was less than 13%. Moreover, the change of the dielectric constant with the frequency was not affected by the concentration of BaTiO 3 nanoparticles, and the polymer nanocomposite showed better frequency stability than the latest reported core-shell or sandwich-structured PMMA/BaTiO 3 system, 8,20,68,73,74 which was attributed to the improvement of the two-phase interface in the system and the dipoles could follow the external electric field change at high frequency. 71,72 With the increase of BT content, the dielectric constant of the capacitor increased accordingly.…”

Toward Excellent Energy Storage Performance via Well-Aligned and Isolated Interfaces in Multicomponent Polypropylene-Based All-Organic Polymer Dielectric Films

“…31 Meanwhile, they could also build up a higher energy barrier for carrier injection, leading to enhanced E b and improved energy storage performance. 12,32,33 The most adopted strategy to construct the perpendicular interfaces is the sandwich structure, which could be constructed through hot pressing, 10,13 layer-by-layer assembly, 34−37 and multilayer coextrusion. 14,16,38−40 However, those methods limit the fabrication of multicomponent all-organic polymer dielectric films on an industrial scale to some extent.…”

“…In general, polymers with high ε r , such as poly­(vinylidene difluoride) (PVDF)-based homo- or copolymers, − and polyamide (PA)-based homo- or copolymers, − were widely expected as the preferred component to achieve high energy storage performance in multicomponent all-organic polymer dielectric films. However, the large polarity of these polymers causes the incompatibility between them and PP.…”

“…Apart from interfacial interactions, carefully designed interfacial topological structures show a high advantage in enhanced energy storage performance, particularly for the interfaces that are perpendicular to the applied electric field direction. − Due to the difference in ε r and conductivities of the components, the charge carriers would accumulate at the interfaces, leading to interfacial polarization. , The accumulated charge carriers could promote larger electric tree diameters and branches, which is beneficial to the enhanced E b . Meanwhile, they could also build up a higher energy barrier for carrier injection, leading to enhanced E b and improved energy storage performance. ,, The most adopted strategy to construct the perpendicular interfaces is the sandwich structure, which could be constructed through hot pressing, , layer-by-layer assembly, − and multilayer coextrusion. ,,− However, those methods limit the fabrication of multicomponent all-organic polymer dielectric films on an industrial scale to some extent. The hot pressing and layer-by-layer assembly are more preponderant on a laboratory scale.…”