High-dielectric-constant polymers as high-energy-density (HED) field effect actuator and capacitor materials

Author(s):  
Cheng Huang ◽  
Qiming Zhang
Materials ◽  
2021 ◽  
Vol 14 (17) ◽  
pp. 4780
Author(s):  
Yushu Li ◽  
Yao Zhou ◽  
Sang Cheng ◽  
Jun Hu ◽  
Jinliang He ◽  
...  

The development of high-energy-density electrostatic capacitors is critical to addressing the growing electricity need. Currently, the widely studied dielectric materials are polymer nanocomposites incorporated with high-dielectric-constant nanoparticles. However, the introduction of high-dielectric-constant nanoparticles can cause local electric field distortion and high leakage current, which limits the improvement in energy density. In this work, on the basis of conventional polymer nanocomposites containing high-dielectric-constant nanoparticles, oriented boron nitride nanosheets (BNNSs) are introduced as an extra filler phase. By changing the volume ratios of barium titanate (BT) and BNNSs, the dielectric property of polymer nanocomposites is adjusted, and thus the capacitive energy storage performance is optimized. Experimental results prove that the oriented BNNSs can suppress the propagation of charge carriers and decrease the conduction loss. Using poly(vinylidene fluoride-co-hexafluoropropylene) (P(VDF-HFP)) as the polymer matrix, the P(VDF-HFP)/BNNS/BT nanocomposite has a higher discharged energy density compared with the conventional nanocomposite with the freely dispersed BT nanoparticles.


2016 ◽  
Vol 840 ◽  
pp. 87-90 ◽  
Author(s):  
Rosyaini Afindi Zaman ◽  
Mohamad Johari Abu ◽  
Saniah Abdul Karim ◽  
Julie Juliewatty Mohamed ◽  
Mohd Fadzil Ain ◽  
...  

In recent years, there has been an increasing interest on high dielectric constant that have significant applications in electronic devices. Dielectric materials have many technological applications such as capacitors, resonators and filters. High dielectric ceramic capacitors based perovskite oxides are necessary for modern electronic devices and are found to be suitable for a wide range of applications. Subramanian et al. discovered the high dielectric constant of CaCu3Ti4O12 (CCTO) ~ 10,000 at room temperature. CCTO has the cubic perovskite crystal structure and high dielectric constant of ~ 104 up to 105 at radio frequency and good temperature stability over a wide temperature range [1,2]. These properties were desired for various microelectronic applications. With the high dielectric constant, the material can store more charge and the values make CCTO an attractive material for ultra-high energy density capacitors. However, this properties can be accomplished if single phase of CCTO is formed. Many research have been done recently on the synthesis of the cubic perovskite CCTO and many techniques are working such as sol-gel route [3], combustion techniques [4], molten salt process [5] and etc., but this technique is difficult and complex process during sample preparation.


2011 ◽  
Vol 1312 ◽  
Author(s):  
Shan Wu ◽  
Minren Lin ◽  
David S-G. Lu ◽  
Qiming Zhang

ABSTRACTBesides energy density, the electric loss at high electric fields is another major concern for many capacitor applications. This paper presents recent works in developing high energy density low loss polymer capacitors. In order to reduce the dielectric loss while maintaining high energy density in poly(vinylidene fluoride-hexafluoropropylene) P(VDF-HFP) and P(VDF-CTFE) (CTFE: Chlorotrifluoroethylene) based polymers, a polymer blend approach was investigated. We show that by blending P(VDF-CTFE) with a proper low loss polymer such as poly(ethylene- chlorotrifluoroethylene) (ECTFE) can lead to marked improvement in the loss of dielectric films. In this study, P(VDF-CTFE) blends films with different wt% of ECTFE have been examined to find a balance between dielectric constant and the loss. In addition, crosslink in the blends has been employed to further improve the dielectric performance of the blends. The results indicate that these blends exhibit an excellent performance: relatively high dielectric constant (~ 6~7) and low loss (~ 0.01) at 1 kHz. For the crosslink blend films, the high field loss is reduced to below 5% with a discharged energy density 4.3 J/cm3 under a field of 300 MV/m.


2015 ◽  
Vol 1740 ◽  
Author(s):  
Masahiko Ando ◽  
Naoki Yoshimoto ◽  
Yuichiro Yoshitake ◽  
Shuji Kato ◽  
Hidekazu Kodama ◽  
...  

ABSTRACTBased on the investigation of mechanism for large dielectric losses in relaxor fluorinated polymers, polyvinylidene fluoride (PVDF) derivatives, a new nanostructure-controlled PVDF based polymer films with low dielectric loss, tanδ < 1% (0.6%), and high dielectric constant, εr = 13 at frequency of 1 kHz, was proposed for electrical energy storage applications. The high dielectric loss was mainly due to the electric-field induced α-β phase transition, and one dimensional extension of P(VDF-TrFE)-g-PEMA films was found to reduce the α phase component resulting in reduction of the dielectric loss while keeping the high dielectric constant. In-situ FTIR measurements suggested a possibility of further reducing the dielectric-loss.


2021 ◽  
Vol 11 (17) ◽  
pp. 8063
Author(s):  
Andrew Burke

In this paper, the design of high energy density dielectric capacitors for energy storage in vehicle, industrial, and electric utility applications have been considered in detail. The performance of these devices depends primarily on the dielectric constant and breakdown strength characteristics of the dielectric material used. A review of the literature on composite polymer materials to assess their present dielectric constants and the various approaches being pursued to increase energy density found that there are many papers in which materials having dielectric constants of 20–50 were reported, but only a few showing materials with very high dielectric constants of 500 and greater. The very high dielectric constants were usually achieved with nanoscale metallic or carbon particles embedded in a host polymer and the maximum dielectric constant occurred near the percolation threshold particle loading. In this study, an analytical method to calculate the dielectric constant of composite dielectric polymers with various types of nanoparticles embedded is presented. The method was applied using an Excel spreadsheet to calculate the characteristics of spiral wound battery cells using various composite polymers with embedded particles. The calculated energy densities were strong functions of the size of the particles and thickness of the dielectric layer in the cell. For a 1000 V cell, an energy density of 100–200 Wh/kg was calculated for 3–5 nm particles and 3–5 µ thick dielectric layers. The results of this study indicate that dielectric materials with an effective dielectric constant of 500–1000 are needed to develop dielectric capacitor cells with battery-like energy density. The breakdown strength would be 300–400 V/µ in a reverse sandwich multilayer dielectric arrangement. The leakage current of the cell would be determined from appropriate DC testing. These high energy density dielectric capacitors are very different from electrochemical capacitors that utilize conducting polymers and liquid electrolytes and are constructed much like batteries. The dielectric capacitors have a very high cell voltage and are constructed like conventional ceramic capacitors.


2015 ◽  
Vol 659 ◽  
pp. 58-63
Author(s):  
Oratai Jongprateep ◽  
Tunchanoke Khongnakhon ◽  
Jednupong Palomas

Rising worldwide demands for energy encourages development of high-efficiency energy storage and capacitor components. Main requirements for dielectric materials employed in fabrication of high energy density capacitors include high dielectric constant, high dielectric breakdown strength, and low dielectric loss. Owing to its high dielectric constant and low dielectric loss [1], barium titanate is among common capacitor materials. Tailoring of dielectric properties of barium titanate can be achieved through controlled chemical composition, microstructure, and crystal structure. Synthesis and processing techniques, as well as doping of barium titanate, can be key factors to control the composition and structure, which consequently contribute to enhancement of dielectric constant in the material.


2021 ◽  
pp. 095400832199352
Author(s):  
Wei Deng ◽  
Guanguan Ren ◽  
Wenqi Wang ◽  
Weiwei Cui ◽  
Wenjun Luo

Polymer composites with high dielectric constant and thermal stability have shown great potential applications in the fields relating to the energy storage. Herein, core-shell structured polyimide@BaTiO3 (PI@BT) nanoparticles were fabricated via in-situ polymerization of poly(amic acid) (PAA) and the following thermal imidization, then utilized as fillers to prepare PI composites. Increased dielectric constant with suppressed dielectric loss, and enhanced energy density as well as heat resistance were simultaneously realized due to the presence of PI shell between BT nanoparticles and PI matrix. The dielectric constant of PI@BT/PI composites with 55 wt% fillers increased to 15.0 at 100 Hz, while the dielectric loss kept at low value of 0.0034, companied by a high energy density of 1.32 J·cm−3, which was 2.09 times higher than the pristine PI. Moreover, the temperature at 10 wt% weight loss reached 619°C, demonstrating the excellent thermostability of PI@BT/PI composites. In addition, PI@BT/PI composites exhibited improved breakdown strength and toughness as compared with the BT/PI composites due to the well dispersion of PI@BT nanofillers and the improved interfacial interactions between nanofillers and polymer matrix. These results provide useful information for the structural design of high-temperature dielectric materials.


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