Significantly Enhanced Breakdown Strength and Energy Density in Sandwich‐Structured Barium Titanate/Poly(vinylidene fluoride) Nanocomposites

Wang, Yifei; Cui, Jin; Yuan, Qibin; Niu, Yujuan; Bai, Yuanyuan; Wang, Hong

doi:10.1002/adma.201503186

Cited by 568 publications

(341 citation statements)

References 29 publications

Supporting

Mentioning

330

Contrasting

Unclassified

Order By: Relevance

“…And more notably, the thermal conductivity of the ''70-3'' multilayer composites is up to 0.447 W m -1 K, and its breakdown strength is still higher than that of pure epoxy. The region of weak electric field, which is formed around the interface between two different layers in the sandwich Al 2 O 3 / epoxy composites, is believed to be the main reason for achieving much higher breakdown strength by blocking the development of electrical trees [25]. The redistribution of electric field among the different layers leads to local electric field much higher than its intrinsic breakdown strength in the nA/epoxy layers, resulting in incomplete breakdown of the nA/epoxy layer.…”

Section: Resultsmentioning

confidence: 99%

Sandwiched epoxy–alumina composites with synergistically enhanced thermal conductivity and breakdown strength

Wang

Yang

et al. 2017

J Mater Sci

View full text Add to dashboard Cite

Development of polymer-based composites with simultaneously high thermal conductivity and breakdown strength has attracted considerable attentions owing to their important applications in both electronic and electric industries. In this study, we successfully design novel epoxy-based composites with nanoAl 2 O 3 /epoxy composite layer sandwiched between micro-Al 2 O 3 /epoxy composite layers, which show synergistically and significantly enhanced thermal conductivity and breakdown strength. Compared with the traditional composites, the bottleneck that both thermal conductivity and breakdown strength cannot be simultaneously enhanced can be overcome successfully. An optimized sandwiched alumina-epoxy composite with 70 wt% micro-Al 2 O 3 fillers in the outer layers and 3 wt% nano-Al 2 O 3 in the middle layer simultaneously displays a high thermal conductivity of 0.447 W m -1 K -1 (2.4 times of that of epoxy) and a high breakdown strength of 68.50 kV mm -1 , which is 6.3 % higher than that of neat epoxy (64.45 kV mm -1 ). The experimental results on the thermal conductivity of multi-layered alumina-epoxy composites were in well accordance with the theoretical values predicted from the series conduction model. This novel technique simultaneously improves thermal conductivity and breakdown strength, which is of critical importance for design of perspective composites for electronic and electric equipments.

show abstract

Section: Resultsmentioning

confidence: 99%

Sandwiched epoxy–alumina composites with synergistically enhanced thermal conductivity and breakdown strength

Wang

Yang

et al. 2017

J Mater Sci

View full text Add to dashboard Cite

show abstract

“…In multilayer composites, extra charge accumulations and polarizations occur at the interfaces between adjacent layers, leading to extra enhancement of permittivity. Meanwhile, the formation and growth of electric trees will be blocked by the interfaces between adjacent layers, resulting in suppressed loss and improved breakdown strength [53]. Besides, the dielectric performances of the multilayer composites could be easily tailored via designing their structures, such as number of layers, stacking sequences, and layer thickness.…”

Section: Introductionmentioning

confidence: 99%

Improved dielectric permittivity and retained low loss in layer-structured films via controlling interfaces

Mao

Shi

Wang

et al. 2018

Adv Compos Hybrid Mater

View full text Add to dashboard Cite

The search for high-performance dielectric materials has long been driven by the urgent needs for various modern electronics. However, enhanced permittivity is always accompanied by elevated loss, which seriously hinders the development and applications of dielectric materials. Herein, negative-k layers were introduced into layer-structured films, forming a new class of multilayer composites consisting of alternately stacked positive-k and negative-k layers. Compared with traditional multilayer composites without negative-k layers, the layered composites containing extra positive-k/negative-k interfaces exhibit superior ability in balancing the contradict parameters: permittivity and loss, yielding substantially enhanced permittivity without sacrificing the low loss. It is indicated that the permittivity was enhanced by the charge accumulations and reinforced polarizations on the interfaces between positive-k and negative-k layers. Meanwhile, the loss induced by the leakage current was suppressed by the blocked transport of carriers between adjacent layers. The trilayered 60-3.5-60 composite exhibits an enhanced dielectric constant (ε′ ≈ 33 @10 kHz) and retained low loss (tanδ ≈ 0.12 @10 kHz) compared with the single-layer BT/PVA composite containing 60 wt% BT fillers (ε′ ≈ 9.5 @10 kHz, tanδ ≈ 0.075 @10 kHz). This research offers an effective way to design and fabricate novel high-performance dielectric materials.

show abstract

“…Different from the single-layer film configuration that is typically used in room temperature dielectric polymers, the rationally designed sandwich structures (18,19) including spatially organized multicomponents exhibit much improved U e and maintain a great η under the operating conditions of DC bus capacitors in electric vehicles. The K value of the sandwichstructured polymer nanocomposites has been enhanced to be 2.5 and 1.8 times those of BOPP and c-BCB/BNNS, respectively, leading to an U e of ∼4.0 J cm −3 and a power density of over 590 MW L −1 at 150°C, which far exceeds those of previous polymer-based dielectric materials under the same conditions.…”

Section: Significancementioning

confidence: 99%

Sandwich-structured polymer nanocomposites with high energy density and great charge–discharge efficiency at elevated temperatures

Liu

Yang

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

350

202

View full text Add to dashboard Cite

The demand for a new generation of high-temperature dielectric materials toward capacitive energy storage has been driven by the rise of high-power applications such as electric vehicles, aircraft, and pulsed power systems where the power electronics are exposed to elevated temperatures. Polymer dielectrics are characterized by being lightweight, and their scalability, mechanical flexibility, high dielectric strength, and great reliability, but they are limited to relatively low operating temperatures. The existing polymer nanocomposite-based dielectrics with a limited energy density at high temperatures also present a major barrier to achieving significant reductions in size and weight of energy devices. Here we report the sandwich structures as an efficient route to high-temperature dielectric polymer nanocomposites that simultaneously possess high dielectric constant and low dielectric loss. In contrast to the conventional single-layer configuration, the rationally designed sandwich-structured polymer nanocomposites are capable of integrating the complementary properties of spatially organized multicomponents in a synergistic fashion to raise dielectric constant, and subsequently greatly improve discharged energy densities while retaining low loss and high charge-discharge efficiency at elevated temperatures. At 150°C and 200 MV m −1 , an operating condition toward electric vehicle applications, the sandwich-structured polymer nanocomposites outperform the state-of-the-art polymer-based dielectrics in terms of energy density, power density, charge-discharge efficiency, and cyclability. The excellent dielectric and capacitive properties of the polymer nanocomposites may pave a way for widespread applications in modern electronics and power modules where harsh operating conditions are present.electrical energy storage | dielectric | polymer nanocomposites | capacitors | high temperature F ilm capacitors store electrical energy in dielectric materials in the form of an electrostatic field between two electrodes. They possess the highest power density (on the order of megawatts) and the best rate capability (on the order of microseconds) among the electrical energy storage devices and are critical for power electronics, power conditioning, and pulsed power applications (1-3). For instance, DC bus capacitors are essential components in the power inverters of electric vehicles for the conversion of direct current to alternating current, which is required to drive the vehicle's motor. Compared with ceramics, polymeric materials offer inherent advantages for capacitors, including their light weight, facile processability, scalability, high breakdown strength, and graceful failure mechanism (1-5). However, dielectric polymers often suffer from low operating temperatures, which fall short of the emerging demands for energy storage and conversion in harsh environments commonly present in automobile, aerospace power systems, and advanced microelectronics (6, 7). For example, to accommodate biaxially oriented polypropylen...

show abstract

Significantly Enhanced Breakdown Strength and Energy Density in Sandwich‐Structured Barium Titanate/Poly(vinylidene fluoride) Nanocomposites

Cited by 568 publications

References 29 publications

Sandwiched epoxy–alumina composites with synergistically enhanced thermal conductivity and breakdown strength

Sandwiched epoxy–alumina composites with synergistically enhanced thermal conductivity and breakdown strength

Improved dielectric permittivity and retained low loss in layer-structured films via controlling interfaces

Sandwich-structured polymer nanocomposites with high energy density and great charge–discharge efficiency at elevated temperatures

Contact Info

Product

Resources

About