Ferroelectric Filler Research Articles

A triboelectric nanogenerator using degradable surface-modified cellulose acetate and ferroelectric gelatin composite nanofibers

High output performance of degradable triboelectric nanogenerators (TENGs) is achieved by synergistically combining nanofibrous structures, chemical surface modification, and composite formation using ferroelectric fillers.

Dissociation mechanism of lithium salt by BaTiO3 with spontaneous polarization

We elucidate the dissociation mechanism of LiFSI induced by the ferroelectric fillers of BaTiO3 and enhanced spontaneous polarization by oxygen vacancy defects.

Effect of ferroelectric filler nanoarchitectonics on the electrical and mechanical properties of the nanocomposite thick films of polyvinylidene fluoride and lanthanum-doped lead zirconate titanate in 0–3 connectivity

Effect of ferroelectric filler nanoarchitectonics on the electrical and mechanical properties of the nanocomposite thick films of polyvinylidene fluoride and lanthanum-doped lead zirconate titanate in 0–3 connectivity

Single material with multiple interfaces: A key one dimensional barium titanate filler for enhancing energy density in polymer nanocomposite

The increasing demand of energy and its storage devices in consumer electronics requires high energy density capacitors. In this context, we proposed a filler of single material with multiple interfaces to enhance the energy density in polymer nanocomposite film. The core-shell polydopamine (PDA) coated BaTiO3 (BT) incorporated in 1D BT architecture filler was prepared by the electrospinning process. In order to investigate the effect of the interfaces, the poly(vinylidene-chlorotrifluoroethylene) (P(VDF-CTFE)) nanocomposite films of a fixed filler (BT, PDA coated BT and 1D core-shell BT) concentration were prepared. The introduction of a ferroelectric filler induces an electroactive phase in P(VDF-CTFE), leading to dielectric constant enhancement by 135% in nanocomposite film. This enhancement in dielectric constant is due to the increased polarizability of nanocomposite film, which was verified by the finite element analysis of electric field distribution. The ferroelectric (polarization vs electric field) loop measurement indicates that the multi-interfaced ferroelectric filler based nanocomposite film exhibits increased maximum polarization of 14.3 μC/cm2, breakdown strength of 5000 kV/cm and improved energy density of 9.9 J/cm3. It implying that an enormous increment (371%) of energy storage as compared to commercial biaxially orientated polypropylene (2.1 J/cm3).

Towards Atomic Level Design of Non-linear Ferroelectric Fillers in Polymer Composites

Towards Atomic Level Design of Non-linear Ferroelectric Fillers in Polymer Composites

Influence of Ferroelectric Filler Size and Clustering on the Electrical Properties of (Ag-BaTiO3)-PVDF Sub-Percolative Hybrid Composites.

The paper presents a study concerning the role of ferroelectric filler size and clustering in the dielectric properties of 20%BaTiO3-80%PVDF and of 20% (2%Ag-98%BaTiO3)-PVDF hybrid nanocomposites. By finite element calculations, it was shown that using fillers with ε > 103 does not provide a permittivity rise in the composites and the effective dielectric constant tends to saturate to specific values determined by the filler size and agglomeration degree. Irrespective of the ferroelectric filler sizes, the addition of metallic ultrafine nanoparticles (Ag) results in permittivity intensification and the effect is even stronger if the metallic nanoparticles are connected to a higher degree with the ferroelectric particles' surfaces. When using coarse ferroelectric fillers, the probability of clustering is higher, thus favoring the permittivity increase by field concentration in small regions close to the interfaces separating dissimilar materials. The modeling results were validated by an experimental dielectric analysis performed in a series of PVDF-based thick films with the same amount of BaTiO3 fillers or with Ag-BaTiO3 hybrid fillers. Similar trends as predicted by simulations were found experimentally but with slightly higher permittivity values which were assigned to the modifications of the polymer phase composition due to the presence of nanofillers and the local sample inhomogeneity (the presence of clustering, in particular for coarse BaTiO3 grains), which create regions with enhanced local fields.

MANUFACTURING OF ELASTOMERIC SUBSTRATES FOR STRETCHABLE PRINTED ELECTRONICS

ABSTRACT Stretchable electronics are being used in applications such as wearable electronics, robotic skin, wearable health-monitoring devices, and smart textiles due to their excellent mechanical conformability through stretching, flexing, twisting, and folding. This work focuses on creating printable stretchable substrates based on butyl rubber (IIR), combined with a ferroelectric filler, barium strontium titanate (BST). BST has unique properties, including the ability to tune the dielectric properties by applying a bias to the substrate. A high loading of BST was incorporated to tailor the dielectric properties of the substrate. This work investigated the effect of three different cure systems on the properties, including interaction with a silver ink. For all cure systems, cure and scorch time decreased with increases in BST loading. A phenolic cure did not affect the ink conductivity, whereas the sulfur-cured systems resulted in nonconductive ink. For the phenolic-cured substrate, the tensile strength increased and the elongation decreased with increasing filler loading. The elastomer could be filled with up to 40 vol. % BST while still maintaining elongation greater than 200%.

Enhanced Output Performance of a Flexible Piezoelectric Nanogenerator Realized by Lithium-Doped Zinc Oxide Nanowires Decorated on MXene.

A flexible piezoelectric composite is composed of a polymer matrix and piezoelectric ceramic fillers to achieve good mechanical flexibility and processability. The overall piezoelectric performance of a composite is largely determined by the piezoelectric filler inside. Thus, different dispersion methods and additives that can promote the dispersion of piezoelectric ceramics and optimal composite structures have been actively investigated. However, relatively few attempts have been made to develop a filler that can effectively contribute to the performance enhancement of piezoelectric devices. In the present work, we introduce the fabrication and performance of the composite piezoelectric devices composed of Li-doped ZnO nanowires (Li: ZnO NWs) grown on the surface of MXene (Ti3C2) via the hydrothermal process. Through this approach, a semiconductor-metal hybrid structure is formed, increasing the overall permittivity. Moreover, the Ti3C2 layer can serve as a local ground in the composite so that the ferroelectric phase-transformed Li: ZnO NWs grown on its surface can be more effectively polarized during the poling process. In addition, the NW-covered surface of Ti3C2 prevents the aggregation of metallic Ti3C2 particles, promoting a more uniform electric field distribution during the poling process. As a result, the output performance of the piezoelectric nanogenerator (PENG) fabricated with a Li: ZnO NW/Ti3C2 composite was greatly improved compared to that of the devices fabricated with Li: ZnO NWs without the Ti3C2 platform. Specifically, the Li: ZnO NW/Ti3C2 composite piezoelectric nanogenerator (PENG) demonstrated a twofold higher output power density (∼9 μW/cm2) compared with the values obtained from the PENG devices based on Li: ZnO NWs. The approach introduced in this work can be easily adopted for an effective ferroelectric filler design to improve the output performance of the piezoelectric composite.

Energy density and efficiency of scalable polymer nanocomposites utilizing core-shell PLZST@Al2O3 antiferroelectric fillers with dielectric gradient

Ferroelectric/polymer based dielectric nanocomposites deliver high power density, but low discharged energy density (Ue) and charge–discharge efficiency (η), which are resulted from high remnant electrical displacement (Dr) of ferroelectric fillers and large dielectric difference between ferroelectrics and polymers, constrain their use in integrated electronic equipments. Here, we provide an effective and low-cost strategy for developing high-energy–density and high-efficiency dielectric nanocomposites by incorporating core–shell structured PLZST@Al2O3 nanoparticles (NPs) as fillers into P(VDF-HFP) polymer matrix. The introduction of PLZST antiferroelectric (AFE) cores with large maximum electrical displacement (Dmax) and small Dr can substantially increase Dmax-Dr values and narrow D-E loops of dielectric nanocomposites. The addition of Al2O3 shells with wide band gap and dielectric constant near that of the P(VDF-HFP) matrix can prevent the charge injection from electrodes and cause the applied electric field evenly distribute, and thus inhibit the leakage current and increase the breakdown strength (Eb), which are confirmed by finite element simulations. Consequently, benefited from large Dmax-Dr of 7.93 µC/cm2 and Eb of 5281.68 kV/cm, PLZST@Al2O3/P(VDF-HFP) nanocomposites with 3 wt% filler contents exhibit simultaneously a large Ue of 17.95 J/cm3 and high η of 75%, which outperform those of all latest NPs/polymer nanocomposites in terms of overall capacitive performances and are even higher than those achieved in polymer nanocomposites loaded with nanowires or nanofibers fabricated by complicated methods. This study exhibits a promising way to promote the industrialized fabrication of dielectric capacitors through capitalizing on the synergy of the dielectric constant gradient, wide band gap and AFE characteristics of the fillers.

Зарядовое состояние композитов полиэтилена с полупроводниковым наполнителем TlGaTe2

The aim of this work is to study the charge state of polymer composites based on high-density polyethylene (HDPE) with a ferroelectric semiconductor filler TlGaTe2 at a volume content of 3, 7, 10 vol.%, And the ferroelectric semiconductor TlGaTe2 itself, as well as to study the temperature dependence of their dielectric constant ε(T) and electrical conductivity ρ(T). It is shown that the introduction of the semiconductor filler TlGaTe2 into the polymer matrix of HDPE makes it possible to control the charge state of polymer composites HDPE/TlGaTe2, which can contribute to a purposeful change in the electrophysical properties of these materials.

Dielectric properties of oligomeric diisocyanate based composites with barium titanate

A series of composites is synthesized on the basis of oligomeric diisocyanate with different contents of ferroelectric filler barium titanate (BaTiO3). The dielectric performances of the obtained composites are found to follow extreme dependences on the filler content with a sharp minimum of the dielectric permittivity and maximum of the dielectric loss tangent at BaTiO3 content 30 vol.%. The characterization of the composite layers by confocal microscopy revealed that the observed dependences of their dielectric properties upon the composition are determined by structural changes of the composites, including percolation, formation of a single infinite cluster and structures of matrix-island and chain types at certain critical concentrations. Keywords: composites, coatings, diisocyanate, barium titanate, dielectric permittivity, dielectric loss, electrochromatography, supercapacitors.

New sorbents for electrochromatography based on polymer-inorganic dielectric composites

Oligomeric diisocyanate based coatings with different contents of barium titanate (BaTiO3) submicron sized particles as a ferroelectric filler are synthesized on poly(dimethylsiloxane) (PDMS) supports. The study of thus obtained coatings using confocal scanning electron microscopy allowed the characterization of their morphology and features of BaTiO3 particles distribution in the polymer binder, including the determination of threshold filler contents corresponding to the formation of an infinite cluster, matrix-island and chain-like structures as well as the percolation. Dielectric permittivity and dielectric losses of the composites are measured and studied depending on BaTiO3 filler content and relating structural features.

A Review on Recent Development and Applications of Dielectric Elastomers

This paper reviews recent developments and applications of dielectric elastomers (DEs) and suggests various techniques to improve DE properties. DEs as smart materials are a variety of electro-active polymers (EAPs) that convert electrical energy into mechanical energy and cause a large deformation when a voltage is applied. The dielectric constant, modulus, and dielectric loss of DEs determine the efficiency of deformation. Among these, the dielectric constant significantly affects their performance. Therefore, various recent approaches to improve the dielectric constant are reviewed, including the enhancement of polarization, introduction of microporous structures in the matrix, and introduction of ferroelectric fillers. Furthermore, the basic principles of DEs are examined, as well as their various applications such as actuators, generators, sensors, and artificial muscles.

Effects of Ferroelectric Fillers on Composite Dielectric Elastomer Actuator

Integrating nano- to micro-sized dielectric fillers to elastomer matrices to form dielectric composites is one of the commonly utilized methods to improve the performance of dielectric elastomer actuators (DEAs). Barium titanate (BaTiO3) is among the widely used ferroelectric fillers for this purpose; however, calcium copper titanate CaCu3Ti4O12 (CCTO) has the potential to outperform such conventional fillers. Despite their promising performance, CCTO-based dielectric composites for DEA application are studied to a relatively lower degree. Particularly, the composites are characterized for a comparably small particle loading range, while critical DEA properties such as breakdown strength and nonlinear elasticity are barely addressed in the literature. Thus, in this study, CCTO was paired with polydimethylsiloxane (CH3)3SiO[Si(CH3)2O]nSi(CH3)3 (PDMS), Sylgard 184, to gain a comprehensive understanding of the effects of particle loading and size on the dielectric composite properties important for DEA applications. The dielectric composites’ performance was described through the figures of merit (FOMs) that consider materials’ Young’s modulus, dielectric permittivity, and breakdown strength. The optimum amounts of the ferroelectric filler were determined through the FOMs to maximize composite DEA performance. Lastly, electromechanical testing of the pre-stretched CCTO-composite DEA validated the improved performance over the plain elastomer DEA, with deviations from prediction attributed to the studied composites’ nonlinearity.

Tuned dielectric and percolation behavior of cold-pressed polyvinyledene fluoride nanocomposites caused by Ni and BaTiO3 fillers

The dielectric and percolation behavior of polymer nanocomposites (PNC) comprising of polyvinylidene fluoride (PVDF)/nanocrystalline nickel (n-Ni) [conducting filler] and PVDF/n-BaTiO3 [ferroelectric insulating filler], prepared under the novel cold press method are compared. Higher effective dielectric constants (ɛeff) of 2400 and 400 at 40 Hz with volume fractions of filler fcon = 0.28 and $$f_{{{\text{BaTiO}}_{3} }} = 0.60$$ were observed, respectively. PVDF/n-Ni composites show percolation behavior associated with insulator to metal transition (IMT) at the percolation threshold (fc), while PVDF/n-BaTiO3 shows an effective electrical behavior due to the sum effect without showing any IMT. The drastic modulation in their dielectric, electrical and percolation behavior are attributed to the nature of filler present in them and has been explained by Percolation theory, Yamada model and VRH models. The universality and non-universality of exponents have been understood within the framework of the above models, the geometry of the fillers and the process conditions. Cold-pressed PNC based on ferroelectric filler are of superior quality for dielectric applications.

Анализ структуры композиционных систем с использованием фрактальных характеристик на примере системы BaTiO-=SUB=-3-=/SUB=--фуллеренол-ЦЭПС

An approach to the study of the relationship between the composition, structure and properties of composites is suggested on the basis of statistical analysis of the distribution of structural elements of the composite between its cross-section fragments and determination of fractal parameters as quantitative characteristics of the material structure. The prospects of this approach are demonstrated on the example of analyzing the microstructure of composites based on cyanoethyl ester of polyvinyl alcohol (CEPVA) with a ferroelectric filler barium titanate (BaTiO3), modified by the precipitation of fullerenol C60(OH)42. The filler modification is shown to result in a decrease of the span and standard deviation of the number of particles between the fragments of the composite, increase in the average number of particles in the fragments, a decrease in the lacunarity of filling the polymer matrix with the filler particles, and increase in the intensity of all the lattice density distribution maxima and correlation radii starting from the second maximum. The obtained results indicate a significant improvement of the filler particles distribution uniformity in the binder and prevention of their agglomeration, thus providing an increase in the permittivity of the composites by an order of magnitude and making the studied materials promising for the application in electronic devices.

Barium-Strontium Titanate/Porous Glass Structures for Microwave Applications

Based on porous silicate glasses obtained by ion exchange, glass-ceramic materials containing a solid solution of barium-strontium titanate with a dielectric constant of more than 100 at microwaves, were synthesized for the first time. Glass-ceramic structures were studied using X-ray diffraction, secondary electron microscopy, Mössbauer spectroscopy and porometry methods. Electrical characteristics such as permittivity and losses of as-prepared and annealed in oxygen medium samples were also investigated at microwaves. It was shown that the method of obtaining porous glasses, due to ion exchange between KFeSi glass and LiNO3 and NaNO3 melts, allows for controlling a wide range of pore sizes and makes it possible to form glass porous structures with pores of the required size. The efficiency of the process of filling a porous matrix with a ferroelectric filler was investigated and the average depth of its penetration was estimated. It was shown that annealing glass-ceramic structures in an oxygen environment had a positive effect on their structural and electrical characteristics. Glass-ceramic structures demonstrate a significant increase in permittivity and a decrease in losses after high-temperature treatment in oxygen.

Enhancement of permittivity in P(VDF‐CTFE)/metal–organic frameworks mixed matrix membranes

AbstractA novel family of mixed matrix membranes (MMMs) with the combination of ferroelectric fluropolymers matrix (P(VDF‐CTFE)) and ferroelectric MOFs fillers ([NH3(CH2)4NH3][M(HCOO)3]2(MCoII, MgII, and MnII), have been synthesized and characterized, including the morphology, structures, and dielectric properties. Dielectric measurements revealed that the permittivity of the composites improved notablely with the introduction of ferroelectric MOFs fillers, while the dielectric loss was comparable to that of the polymer matrix. And also, interestingly, the enhancement of permittivity evidently dependent on the quantity and dielectric behavior of MOFs fillers, which may be valuable to the dielectric regulation of the polymer/MOFs MMMs. In addition, two different preparation methods were adopted respectively, including blending and electrospinning‐hot pressing. The comparison of the two preparation methods revealed that the blending MMMs exhibit higher permittivity and higher dielectric loss than that of the electrospinning‐hot pressing MMMs. To our knowledge, this is a novel research of high‐εr dielectric MMMs fabricated by ferroelectric MOFs and ferroelectric fluropolymers, and this work may provide a new perspective on the further research of high‐κ dielectric MMMs and the industrial application of ferroelectric MOFs.

Ultrahigh Energy Efficiency and Large Discharge Energy Density in Flexible Dielectric Nanocomposites with Pb0.97La0.02(Zr0.5SnxTi0.5-x)O3 Antiferroelectric Nanofillers.

Flexible dielectric capacitors have been widely studied recently on account of their fast charge-discharge speed, high power density, and superior wearable characteristics. Inorganic ferroelectric fillers/polymer matrix composites combining large maximum electric displacement (Dmax) of ferroelectric materials with good flexibility and high electric breakdown strength (Eb) of the polymer are regarded as the most promising materials for preparing flexible dielectric capacitors with superior energy storage properties. However, simultaneously achieving large discharge energy density (Wd) and high energy efficiency (η) in these composites remains challenging on account of a large remnant electric displacement (Dr) and low Dmax - Dr values of ferroelectric fillers. In contrast, antiferroelectrics (AFEs) exhibit near zero Dr and larger Dmax - Dr values and are thus attractive composite fillers to simultaneously achieve large Wd and high η. On the basis of these factors, in this report, we design and prepare Pb0.97La0.02(Zr0.5SnxTi0.5-x)O3 (PLZST) AFE nanoparticles (NPs)/poly(vinylidene fluoride-co-hexafluoropropylene) (P(VDF-HFP)) nanocomposites and investigate the effects of the Sn and AFE NPs contents on the energy storage capacity of the nanocomposites. Through reasonable adjustment of the Sn content and the PLZST AFE fillers content, because of the large Dmax - Dr value of 7.75 μC/cm2 and small Dr value of 0.26 μC/cm2 at the Eb as high as 3162 kV/cm, the Pb0.97La0.02(Zr0.5Sn0.38Ti0.12)O3 AFE NPs/P(VDF-HFP) polymer nanocomposite with 7 wt % fillers exhibits the most superior energy storage properties with an ultrahigh η of 93.4% and a large Wd of 12.5 J/cm3. These values are superior to those of the recently reported dielectric nanocomposites with a single-layer structure containing ferroelectric nanowires, nanofibers, nanobelts, nanotubes, and nanosheets or core-shell structure fillers, which are prepared via a very complicated method. This work not only shows that, in principle, the polarization characteristics of the composites depend mainly on those of the inorganic fillers but also demonstrates a convenient, effective, and scalable way to fabricate dielectric capacitors with superior flexibility and energy storage capacities.

Heat Resistance and Electrophysical Characteristics of Polyheteroarylenes and Ferroelectric–Polymer Film Composites Based on Them

Structurally related poly(amido-o-hydroxy amides) derived from 5,5-methylenebis(2-aminophenol) with tetramethylsiloxane and heteroaromatic (benzoxazole and benzotriazole) fragments incorporated in the second amine component or formed by polyheterocyclization of the corresponding prepolymers were prepared. The effect of modifying fragments introduced into the base poly(o-hydroxy amide) on the heat resistance of powders and films and of films of photosensitive compounds based on the synthesized polymers with the naphthoquinone diazide component was analyzed. The electrophysical parameters of the polymer films and film composites with a nanodispersed ferroelectric filler, (PZT: ceramic powder with the composition Pb0.81Sr0.04Na0.075Bi0.075(Zr0.58 Ti0.42)O3, Russian brand PZT-1), prepared on the basis of modified polymer binders, were determined. Introduction of 20 mol % sulfur-containing fragments into the polymer binder ensures a 50–65˚C increase in the heat resistance for all types of films without increasing the level of the dielectric loss for the composite coatings.