Dielectric Nanocomposites Research Articles

Sensing the Aging State of Nomex-Based Nanocomposite Insulation by Dielectric Spectroscopy

Sensing the Aging State of Nomex-Based Nanocomposite Insulation by Dielectric Spectroscopy

The energy-storage density of Polymers/BNBT6 nanocomposites with high breakdown field

Ceramic/polymer dielectric composites show significant potential for energy storage devices in advanced microelectronic applications. However, an excessive quantity of inorganic nanofillers within the polymeric matrix can lead to a substantially unequal distribution of the electric field, which may impede the improvement of energy storage density. Herein, 0.94Bi0.5Na0.5TiO3-0.06BaTiO3 (BNBT6) nanoparticles were synthesized using a combined solid-phase method followed by sieving. The silane coupling agent KH560 was used to modify the nanoparticles. Additionally, polyphenylene oxide (PPO), polytetrafluoroethylene (PTFE), and perfluoroalkyl (PFA) were utilized as matrices. The surface modification enhanced the interfacial coupling interaction between BNBT6 and the polymers, resulting in a lower concentration of interfacial hole defects. The findings demonstrated that BNBT6@KH560/PPO nanocomposites attained a high Wrec (2.71 J cm−³) and an excellent of η ∼ 81.1 % with 50 wt% BNBT6@KH560 nanofiller at 1550 kV cm−1. Furthermore, the exceptional frequency and thermal stability of BNBT6@KH560/PPO nanocomposites made it a strong contender for future portable energy devices. This work presents a feasible solution for synthesizing high-performance dielectric nanocomposites using straightforward preparation techniques.

Enhanced energy storage density and efficiency of nanocomposite dielectrics by modifying polymer matrix and aminated boron nitride nanosheet

Polymers and fillers with high dielectric constant (εr), charge-discharge efficiency (η) and breakdown strength (Eb) are fundamental to the development of nanocomposite dielectrics for superior energy storage capabilities. Herein, high-εr P(VDF-TrFE) is used to prepare the P(VDF-TrFE)-g-PMMA matrix with elevated εr and η, then the P(VDF-TrFE)-g-PMMA/BNNS-NH2 nanocomposites with uniformly oriented distribution of h-BN is obtained by a squeegee casting process using amino-boron nitride (BNNS-NH2) as fillers. Thanks to the limiting effect of PMMA and the high insulating effect of BNNS-NH2, the energy storage density (Ue) of the nanocomposite is up to 15.1 J/cm3 at 500 MV/m, which is 358 % and 182 % of the original P(VDF-TrFE). Furthermore, the η could reach to 72 %, being 184 % of neat polymer. These results demonstrate that the coordinated enhancement of Ue and η is critical for high performance energy storage, which provide scientific and technological support for the practicability of PVDF-based dielectrics.

Surface‐Confined Winding Assembly of SiO2 on the Surface of BaTiO3 Leading to Enhanced Performance of Dielectric Nanocomposites

Surface‐Confined Winding Assembly of SiO₂ on the Surface of BaTiO₃ Leading to Enhanced Performance of Dielectric Nanocomposites

Constructing polyimide-based nanocomposite dielectrics with superior high‐temperature energy storage performance via using ternary structure strategy

To maintain low leakage current and energy storage stability of polyimide at high temperature and electric field, ternary structure strategy is used to construct polyimide-based nanocomposite dielectrics, relating to cross-linked structure, sandwich structure and inorganic filler structure. Based on synergistic effect, energy storage properties of crosslinked polyimide-based sandwich‐structured nanocomposite films is significantly improved, in which cross-linked polyimide composited layers with 2 wt% hexagonal boron nitride nanosheets are selected as two outer insulating layers and cross-linked polyimide composited layer with 1 wt% barium titanate nanoparticles is employed as central polarization layer. When volume ratio of middle polarization layer is 10 % (denoted as N-10 T-N), the maximum Ud of 11.6 J/cm3 and η of 87 % are achieved at room temperature. At 150 °C, the Ud of N-10 T-N is 5.1 J/cm3. This study provides the experience for the development of polyimide dielectrics with high capacitive properties over a wide temperature range.

Self-assembly TiO2@Silane@SiO2 core-shell as s-scheme heterojunction photocatalyst against methylene blue degradation: synthesis and mechanism insights

Pollutants are the most critical threats to the health of water resources. On this basis, fabricating a core-shell as an S-scheme heterojunction photocatalyst for the treatment of wastewater from methylene blue (MB) dye was aimed in this research. In this study, TiO2-doped silanized silica dielectric nanocomposites were synthesized as self-assembly TiO2@Silane@SiO2 heterojunction through sol-gel and solvothermal methods using tetrabutyl orthotitanate (TBOT) as precursor followed by calcination at 650 °C for 3 h. Silanization of silica nanoparticles was done at two different concentrations. The results showed that layer-by-layer synthesis (i.e. self-assembly of APTES on SiO2, precipitation of TiO2 layer on it by sol-gel technique and then calcination) was the optimum preparation method. The structural and morphological features were investigated by XRD, FTIR, BET, TGA-DTG, FE-SEM, EIS and ESR techniques. It was found that the band gap energy of nanocomposite particles reduced from 3.14 eV for the sample prepared by the solvothermal method (i.e. without APTES) to 2.91 eV (i.e. shifting the light absorption from UV to the visible region) for the sample prepared by the sol-gel layer-by-layer method. The prepared samples were used against the photo-degradation of MB. TiO2@Silane@SiO2 core-shell nanoparticles exhibited efficient photocatalytic degradation against MB with a photodegradation efficiency of 85 % under UV and 60 % under visible irradiation. Finally, the prepared nanocomposite particles were incorporated to an emulsion acrylic resin to prepare photocatalytic polymer film. The prepared films were evaluated for photocatalytic degradation of MB stain and mechanical performances. It was found that the TiO2@Silane@SiO2 nanocomposite particles that prepared by layer-by-layer method caused about 56 % improvement in hydrophobicity, 276.7 % increment in the tensile strength, 109.6 times enhancement in the modulus, 381.4 times enhancement in the toughness and 57.6 times improvement in the elongation at break of the acrylic film compared to the pure TiO2-containing acrylic film, respectively.

Simultaneous improvements in energy density and thermal conductivity of PAN polymer nanocomposites enabled by core-shell structure BZCT@BNNS nanofibers

If the heat generated by electronic devices in high-power applications cannot be dissipated in a timely manner, it will not only affect the use of the equipment but also reduce its service life. Therefore, there is an urgent need to develop thin films of dielectric nanocomposites with high thermal conductivity, high energy storage, and excellent flexibility and electrical insulation performance. In this study, we reported the successful preparation of BZCT nanofibers (BZCT NFs) and core-shell structures BZCT@BNNS nanofibers using electrospinning and coaxial electrospinning techniques, respectively, and there were used to composite with polyacrylonitrile (PAN) polymer matrix to prepare BZCT NFs/PAN and BZCT@BNNS/PAN dielectric nanocomposites thin film. Research has found that when the shell thickness of BNNS is 15 nm and BZCT@BNNS (15 nm) volume fraction is 20 vol%, the comprehensive performance of the dielectric nanocomposites is the best, with thermal conductivity and energy storage performance of 3.36 W m−1K−1 and 12.23 J/cm3, respectively. Therefore, the nanocomposites thin film can be used as a potential high-performance dielectric material for thermal management applications in high-power density electronic devices.

Dielectric nanocomposites with superb high-temperature capacitive performance based on high intrinsic dielectric constant polymer

Dielectric nanocomposites with superb high-temperature capacitive performance based on high intrinsic dielectric constant polymer

Confining Nano-ZrO2 in Nanodomains Leads to Electroactive Artificial Muscle with Large Deformation.

Dielectric elastomers generate muscle-like electroactive actuation, which is applicable in soft machines, medical devices, etc. However, the actuation strain and energy density of most dielectric elastomers, in the absence of prestretch, have long been limited to ∼20% and ∼10 kJ m-3, respectively. Here, we report a dielectric elastomer with ZrO2 nanoparticles confined in nanodomains, which achieves an actuation strain >100% and an energy density of ∼150 kJ m-3 without prestretch. We decorate the surface of each nanoparticle with a layer of a diblock oligomer, poly(acrylic acid-b-styrene). The surface-decorated nanoparticles coassemble with a triblock copolymer elastomer, poly(styrene-b-(2-ethylhexyl acrylate)-b-styrene) during cosolvent casting. Consequently, the nanoparticles are confined in the polystyrene nanodomains, which results in a dielectric elastomer nanocomposite with a low modulus, high breakdown strength, and intense strain-hardening behavior. During the actuation, the nanocomposite avoids the snap-through instability that most elastomers would suffer and achieves a superior actuation performance.

High-temperature high-performance capacitive energy storage in polymer nanocomposites enabled by nanostructured MgO fillers

High-temperature high-performance polymer dielectric capacitors are essential for cutting-edge electronics and high-power systems operated in harsh environment conditions. Herein, dielectric composites comprising polyetherimide (PEI) polymers and easily prepared magnesium oxide (MgO) nanoparticles are fabricated by tape casting to promote capacitive performance at high temperatures. Benefiting from high-insulation behavior and wide bandgap of the MgO nanoparticles, the designed PEI nanocomposites deliver the significantly suppressed leakage current density and prominent enhancement of the breakdown strength, especially under high temperatures, the rationality of which is further revealed by finite element simulations on high-field distribution and electrical tree evolution. Accordingly, the nanocomposites containing ultra-low loading volume (0.5 vol%) MgO nanoparticles endow a large discharged energy density (~ 6.60 J cm−3) at 150 °C, which is ahead of most investigated 0–3 dielectric nanocomposites with inorganic fillers. Moreover, the excellent fatigue resistance at 150 °C is simultaneously achieved. This study demonstrates a practical route to develop scalable high-temperature polymer nanocomposite dielectrics blended with inorganic nanoparticles with superior capacitive performance, thus accelerating the development of dielectric polymer capacitors.

Ultrahigh Dielectric Energy Density and Efficiency in PEI‐Based Gradient Layered Polymer Nanocomposite

AbstractDielectrics with high‐energy‐storage performance are highly desired for increasing compact‐size energy storage, and integration of modern power electronics. However, an ever‐existing challenge is to achieve both high efficiency (η) and high energy density (Ue). Here, a gradient‐layered (five‐layer) polyetherimide (PEI)‐based nanocomposite is presented. Different from traditional layered structures (modulation of filler volume fraction), multistage gradient interfaces are constructed by modulating the particle sizes of barium titanate nanoparticles (BaTiO3 NPs) to decrease sequentially from top to bottom. In this structure, three BaTiO3 NPs/PEI layers are clamped by two boron nitride nanosheets (BNNSs)/PEI layers. It is demonstrated that the gradient structure can suppress breakdown and confer high interfacial polarization, simultaneously. Consequently, the nanocomposite possesses an enhanced Ue of 16.38 J cm−3, and an ultrahigh η of 97.79%, far exceeding previously reported polymer nanocomposites. Furthermore, this nanocomposite also demonstrates satisfactory high‐temperature energy storage performances, achieving a Ue of 7.36 J cm−3 and an η of 83.12% at 150 °C. This gradient layered structure design opens a new way to explore high‐performance dielectric polymer nanocomposite with both ultrahigh Ue and η.

Polymer nanocomposites with concurrently enhanced dielectric constant and breakdown strength at high temperature enabled by rationally designed core-shell structured nanofillers

Polymer dielectrics are required to maintain high energy density at elevated temperatures for advanced power and electronic systems. Herein, we report a novel solution-processed core-shell structured polyimide (PI) nanocomposite with moderate dielectric constant HfO2 core and wide-bandgap Al2O3 shell, effectively addressing the typical trade-off between dielectric constant and breakdown strength in dielectric nanocomposites predominant at elevated temperatures. The formation of improved dielectrically matching interfaces by the rationally designed dielectric constant gradient from core-shell-matrix remarkably mitigates the distortion of the electric field around the interfaces, resulting in a high breakdown strength. Wide band gap Al2O3 shell also introduces deeper traps to impede the conduction loss. The validity of Al2O3 shell has been proved via experiments and simulations. Accordingly, HfO2@Al2O3/PI nanocomposite exhibits an excellent charge-discharge efficiency of 91.7 % at 300 MV/m and a maximum discharged energy density of 2.94 J/cm3 at 150 °C, demonstrating its potential for high-temperature energy storage.

Polyetherimide nanocomposite with enhanced mechanical, thermal and dielectric properties by incorporating synergistically exfoliated‐chemical functionalization induced hexagonal boron nitride nanosheets

AbstractThe present study aims to improve the mechanical, thermal and dielectric properties of polyetherimide (PEI) nanocomposite via simplified method, involving the creation of a nanocomposite using PEI incorporated with exfoliated‐chemical functionalization induced hexagonal boron nitride nanosheets (BNNS). XRD, FTIR and Raman elucidated the chemical structure of functionalized BNNS and indicated the success preparation of functionalized BNNS. Functionalization effectively improved the compatibility of nanocomposites and contributed to the property improvements. Morphological analysis unveiled a compact and dense microstructure within the nanocomposites in correlation with functionalized BNNS. Broad band dielectric spectroscopy revealed excellent dielectric properties of produced PEI nanocomposite. DMA testing verified a noteworthy enhancement in both Tg and storage modulus upon incorporating of BNNS. In summary, this comprehensive investigation highlights the impact of functionalized BNNS on mechanical, thermal and dielectric properties of developed PEI dielectric nanocomposite and is expected to expand the application of PEI in the field of high‐temperature energy storage.Highlights Polyetherimide (PEI) was used as polymer matrix and boron nitride derivatives as dielectric fillers to prepare PEI dielectric nanocomposite. Due to the influences of dielectric properties by interface polarization effect and the local distribution of electric field of the fillers in PEI matrix, the dielectric constant, breakdown strength and energy storage density of PEI nanocomposites were obviously improved compared with pure PEI. The effects of interfacial interactions between PBNNS and PEI contributes to the uniform dispersion and comprehensive property improvements of PEI dielectric nanocomposites. This work presents a systematic investigation into the fabrication of PEI/BNNS nanocomposite using a one‐step solution blending method, inspiring the research and development of PEI in the energy storage applications areas in the future.

Preparation and performance study of polyurethane/ kaolinite nanocomposite insulation materials

Abstract Polyurethane foam insulation materials exhibit excellent noise reduction, shock absorption and vibration damping capabilities while being cost-effective and easily moldable. They have found widespread applications in diverse fields such as automotive, machinery, packaging, insulation, healthcare and construction. However, the application range of this traditional organic material is limited by issues related to thermal stability and flame retardancy. By achieving uniform dispersion of nanoparticles, composite materials exhibit enhanced comprehensive properties in terms of flame retardancy, oxidation resistance, physicochemical stability and structural performance. Polyurethane/Kaolinite nanocomposite insulation materials were prepared by using the in situ intercalation compounding method. X-ray diffractometer, Fourier infrared spectrophotometer, thermogravimetric analyzer and scanning electron microscope were used to characterize the thermal stability of the composite material obtained under different preparation conditions and the state of the nanomaterial in the system. The results showed that the composite material with good dispersion of kaolinite in the matrix was obtained by effective surface modification through dimethyl sulfoxide. The doping of low-concentration kaolinite can improve the thermal stability of polyurethane. When the mass fraction of nano-kaolinite is 5%, the initial decomposition temperature of the composite system is 47°C higher than that of pure polyurethane and the system achieves the highest thermal stability.

Ultrahigh energy density in dielectric nanocomposites by modulating nanofiller orientation and polymer crystallization behavior

High-energy density dielectrics for electrostatic capacitors are in urgent demand for advanced electronics and electrical power systems. Poly(vinylidene fluoride) (PVDF) based nanocomposites have attracted remarkable attention by intrinsic high polarization, flexibility, low density, and outstanding processability. However, it is still challenging to achieve significant improvement in energy density due to the common contradictions between electric polarization and breakdown strength. Here, we proposed a novel facile strategy that simultaneously achieves the construction of in-plane oriented BaTiO3 nanowires and crystallization modulation of PVDF matrix via an in-situ uniaxial stretch process. The polar phase transition and enhanced Young's modulus facilitate the synergetic improvement of electric polarization and voltage endurance capability for PVDF matrix. Additionally, the aligned distribution of nanowires could reduce the contact probability of nanowire tips, thus alleviating electric field concentration and hindering the conductive path. Finally, a record high energy density of 38.3 ​J/cm3 and 40.9 ​J/cm3 are achieved for single layer and optimized sandwich-structured nanocomposite, respectively. This work provides a unique structural design and universal method for dielectric nanocomposites with ultrahigh energy density, which presents a promising prospect of practical application for modern energy storage systems.

High-temperature dielectric nanocomposite film of 2D Bi4Ti3O12/ABS with excellent energy storage performance

The utilization of high-temperature dielectrics in capacitive energy storage is of great significance in contemporary electronic systems. Nevertheless, the thermal stability of most emerging polymers exhibits a significant decline in their energy storage capacity as temperatures rise. In this study, a unique type of 2D Bi4Ti3O12 nanofillers was synthesized in order to improve the breakdown strength. A nanocomposite consisting of Bi4Ti3O12/poly(acrylonitrile-butadiene-styrene) (ABS) was synthesized with the aim of attaining enhanced dielectric characteristics and energy storage density under elevated temperatures. The Bi4Ti3O12/ABS nanocomposites exhibited notable temperature stability in relation to their dielectric and energy storage capabilities across a temperature range spanning from room temperature to 120 °C. Ultrahigh discharged energy density (Ue) of 12.44 J/cm3 for 3 wt%- Bi4Ti3O12/ABS nanocomposites and high efficiency of 87 % under 550 MV/m were achieved at room temperature. An excellent Ue of 9.12 J/cm3 and high efficiency of 86.2 % for 3 wt%- Bi4Ti3O12/ABS nanocomposites were also observed in 3 wt%- Bi4Ti3O12/ABS nanocomposites under 450 MV/m at 120 °C, which was 117 % and 114 % of ABS films. These capacitive performances could match or be higher than previously reported values for high-temperature capacitor applications.

Enhanced Energy Storage in PVDF-Based Nanocomposite Capacitors through (00l)-Oriented BaTiO3 Single-Crystal Platelets.

Flexible nanocomposite dielectrics with inorganic nanofillers exhibit great potential for energy storage devices in advanced microelectronics applications. However, high loading of inorganic nanofillers in the matrix results in an inhomogeneous electric field distribution, thereby hindering the improvement of the energy storage density (Ue) of the dielectrics. Herein, we proposed a strategy that utilized (00l)-oriented barium titanate (BT) single-crystal platelets to fabricate trilayered nanocomposite dielectrics for energy storage applications. The trilayered nanocomposites consisted of two high-permittivity layers of (Ta2O5, Al2O3) codoped TiO2 nanoparticles (Ta-Al@TiO2 nps) dispersed in a poly(vinylidene fluoride) (PVDF) matrix to facilitate large electric displacement and a middle layer of (00l)-oriented BT single-crystal platelets to provide high breakdown strength. Hence, the trilayered PVDF/Ta-Al@TiO2 nps/BT single-crystal platelet nanocomposite film attains an outstanding Ue of 16.9 J cm-3 at 370 kV mm-1, which is ∼625% higher than that of the single-layer PVDF/Ta-Al@TiO2 nps film. Finite element simulation further clarified that the successive inner layer of highly (00l)-oriented BT single-crystal platelets could effectively restrain the propagation of electrical treeing in trilayered nanocomposites. This research offers an effective approach for developing flexible dielectric capacitors with an excellent energy storage performance.

Polyimide nanocomposites for high‐temperature capacitive energy storage applications by incorporating functional graphene oxide nanosheets: Design, preparation, and mechanism

AbstractHerein, graphene oxide (GO) and its derivative, reduced GO (rGO) and p‐phenylenediamine (PPD) functionalized GO (GO‐g‐PPD) were first synthesized and selected as dielectric fillers, and then GO/polyimide (PI), rGO/PI, and GO‐g‐PPD/PI dielectric nanocomposites were fabricated through in situ polymerization‐composition strategy. Fourier transform infrared, Ram, and x‐ray diffraction analysis confirmed the success synthesis of rGO and GO‐g‐PPD dielectric fillers. The mechanical properties showed that GO‐g‐PPD/PI nanocomposites exhibited the highest tensile strength and elasticity modulus. TGA analysis revealed that the enhancement of thermal stability by addition of dielectric fillers. The dielectric constant of 2.5 wt.% GO‐g‐PPD/PI nanocomposites reached 25.05, which was 8.55 times that of pure PI (2.93). Energy storage performance tests showed that the energy storage density of GO‐g‐PPD/PI containing 2 wt.% filler reached 0.77 J/cm3, which was 71% higher than pure PI. These findings underscore the potential of GO derivative as a cost‐effective reinforcement for PI dielectric nanocomposites for high‐temperature capacitive energy storage applications.

2D Perovskite Nanosheet‐Driven Polymeric Nanocomposites as Gate Dielectrics for Flexible Negative‐Capacitance Applications

AbstractDesigning composite gate dielectrics tailored by incorporating inorganic perovskite nanofillers into a polymer matrix to develop flexible low‐voltage transistors can be challenging because homogeneous dispersion of nanomaterials in the matrix is difficult to achieve; thus, degradation of the electrically insulating properties of nanocomposite layers is often observed. In this study, nanocomposite dielectrics are presented that consist of 2D Ba5Ta4O15 nanosheets (BTO NSs) for the first time. Perovskite BTO is introduced using the Langmuir–Blodgett method to construct a precise and pinhole‐free interface for the homogeneous assembly of 2D nanosheets. Its high k value and ferroelectric properties, which arise from the perovskite structure, can be harnessed to achieve attractive polarization and remarkable electronic properties. The 2D BTO NSs can also be utilized as phase crystallization fillers to enhance the ferroelectric properties of polyvinylidene fluoride (PVDF). Additionally, the multilayer PVDF/perovskite nanosheet hybrid dielectric, which reaches an unprecedentedly high dielectric constant of 22.4, exhibits effective dielectric relaxation related to the interfacial induced ferroelectric polarization and decisive negative‐capacitance response.

The poly (arylene ether urea) double interface layer formed in PEEU@HfO2/PEI nanocomposites enables enhanced dielectric and energy storage performance

Polyetherimide (PEI) has great potential as a dielectric because of its high-temperature resistance, but its low energy storage density limits practical applications. Incorporating hafnium dioxide (HfO2) with a moderate dielectric constant (k) and wide bandgap can simultaneously enhance the polarization intensity of PEI and potential barriers for charge injection. Nevertheless, the poor compatibility between HfO2 and PEI inevitably introduces defects, thereby weakening the inhibitory effect on dielectric loss. To tackle this issue, an organic double interface layer is introduced to enhance dielectric performance, where the polar poly(arylene ether urea) (PEEU) containing hydrogen bonds can ensure the layer's compactness. Notably, its non-bonding urea groups serve as deep traps to capture migrating carriers, and the gradient k values of HfO2, PEEU, and PEI help mitigate electric field distortions at the interface, therefore enhancing the suppression of conduction loss. The polarity of PEEU and the introduction of multiple interfaces significantly contribute to an increased k (maximum 9.7, at 1 kHz). At 300 kV mm−1, 5 vol% PEEU@HfO2/PEI achieves a discharged energy density of 3.3 J cm−3 and a high charge-discharge efficiency of 83 %, surpassing 5 vol% HfO2/PEI by 1.95 and 2.44 times, respectively. The further COMSOL simulation verifies and proves this work as a novel design strategy for nanocomposite dielectrics.