Enhancement of dielectric properties and energy storage density in poly(vinylidene fluoride-co-hexafluoropropylene) by relaxor ferroelectric ceramics

Abstract

IntroductionDielectric materials with high discharged energy density have attracted scientific and commercial interest due to the prospect of application on electronic devices such as radar, lasers, defibrillators, rail guns, and pace makers. 1-5 However, the technologies in current states suffer from low energy density, which make them bulky and costly. One of the desirable strategy to increase the energy density of these materials is to apply 0−3 type inorganic/polymer composites (zero-dimensional fillers in a three-dimensionally connected polymer matrix), because they hold high dielectric strength and excellent processability of the polymer, which overcome the limitations associated with the conventional inorganic ceramic and organic dielectric materials. [6][7][8][9][10][11][12][13] In general, the discharged energy density (J) of dielectric materials is related to the equation as:where D max and D r are the maximum electric displacement and remnant electric displacement of the materials, respectively, E is the applied electric field. Electric displacement (D) is defined as: 0 r 5 introducing relaxor ferroelectric ceramics to polymer matrix would be meaningful to prepare flexible dielectric materials with improved discharged energy density and energy efficiency.In this paper, relaxor ferroelectric PMN-PT ceramic particles were synthesized by molten-salt growth method. The synthesized PMN-PT ceramic particles were modified by dopamine before being introduced to the poly(vinylidene fluoride-co-hexafluoropropylene) (P(VDF-HFP)) matrix. Compared with the pristine PMN-PT, the modified PMN-PT particles dispersed homogeneously in the composites, strong interfacial adhesion with the polymer matrix and the composite showed improved dielectric properties with modified PMN-PT particles. The energy density storage of the composites was as high as 1.02 J/cm 3 , which is more than four times over the pure P(VDF-HFP) matrix. The findings of this research could provide an effective approach to build high energy density storage capacitors. Experimental section MaterialsThe chemicals were obtained from the following sources and used without further purification: PbO (kermel, China, 99%), Nb 2 O 5 (Sinopharm, China, 99%), [(MgCO 3 ) 4 Mg(OH) 2 ]5H 2 O (Sinopharm, China, 99%), TiO 2 (Anatase, Aladdin, 99.8%), KCl(Sinopharm, China, 99.5%). Dopamine hydrochloride (Alfa, 99%), P(VDF-HFP) (Aldrich, pellets with less than 15% of HFP), and other reagents are all analytically pure. 11dopamine. A polymer layer with the thickness of ~7 nm can be clearly observed on the surface of the PMN-PT particle. The corresponding high-resolution image of the functionalized PMN-PT particle is exhibited in Fig. 4b. An obvious interface with discrepant high resolution stripe can be seen in the two sides of the interface, which was agreed with the result in Fig. 4a. Fig. 4c shows the TGA curves of pristine PMN-PT, functionalized PMN-PT particle, and the pure dopamine. The amount of the dopamine coated on the surfaces of the PMN-PT particle is characteri...

High Energy Density Dielectrics Based on PVDF‐Based Polymers

“…On the other hand, to improve the dielectric properties, the 0‐3 composites of PVDF‐based polymers and ferroelectric oxide nanoparticles, which have much higher dielectric properties than normal dielectrics, have been intensively studied. These oxides include BaTiO 3 , Pb(Zr,Ti)O 3 , PMN‐PT, Na 1/2 Bi 1/2 TiO 3 , etc. Because the dielectric permittivity of PVDF‐based polymers is typically around two orders of magnitude lower than that of ferroelectric oxides, the applied electric field on the nanocomposites could concentrate in the polymers, resulting in a lower breakdown field.…”

Interface design for high energy density polymer nanocomposites

“…A variety of modifiers have been used, as shown in Fig. 5, which include dopamine, 73,74 silanes, 75 phosphonic acid, 76 ethylene diamine, 77 polyvinyl alcohol, 78 and paraffin. 79 These organics have been utilized to modify the surfaces of inorganic fillers and are of interest due to their simple treatment process, for example by solution mixing.…”

“…Examples of organic modifiers for surface engineering of a ceramic filler particle, in this case BaTiO 3 [73][74][75][76][77][78][79]. 4430 | Chem.…”

Building Hierarchical Interfaces Using BaSrTiO3 Nanocuboid Dotted Graphene Sheets in an Optimized Percolative Nanocomposite with Outstanding Dielectric Properties

“…High‐performance dielectric materials with high relative permittivity and supressed dielectric loss are of interest for potential electrical and electronic applications, such as energy storage devices, capacitor, artificial muscles, etc . Recently, ceramic/polymer insulative composites that combine high permittivity ferroelectric ceramics (BaTiO 3 , Pb(Zr,Ti)O 3 , Pb(Mg 1/3 Nb 2/3 )O 3 –PbTiO 3 , BaSrTiO 3 (BST)) with flexible polymers have been examined to exploit the beneficial dielectric properties, insulating properties, and flexibility of each phase . However, due to the low permittivity of the polymer matrix phase the maximum relative permittivity that can be achieved is usually limited to less than 100, even when the composite incorporates high levels of ferroelectric ceramic particles (>50 vol%).…”