Azobenzene-functionalized polymers by ring-opening metathesis polymerization for high dielectric and energy storage performance

2019 ◽  
Vol 10 (19) ◽  
pp. 2447-2455 ◽  
Author(s):  
Yu Zhu ◽  
Cuihong Ma ◽  
Huijin Han ◽  
Ruyi Sun ◽  
Xiaojuan Liao ◽  
...  

Block copolymers with push–pull azobenzene pendants and core–shell nanostructures exhibited high and regulated dielectric constants by photoisomerization of azobenzene groups, low dielectric loss, and high energy density.

2015 ◽  
Vol 3 (37) ◽  
pp. 9740-9747 ◽  
Author(s):  
Y. N. Hao ◽  
X. H. Wang ◽  
S. O'Brien ◽  
J. Lombardi ◽  
L. T. Li

BaTiO3/PVDF nanocomposite films with high flexibility and gradated BaTiO3 distribution structure are fabricated. These films show high dielectric constants of 20–25, a maximal discharged energy density value of 19.37 J cm−3 and dielectric breakdown strengths of up to 495 kV mm−1.


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.


Molecules ◽  
2021 ◽  
Vol 26 (6) ◽  
pp. 1535
Author(s):  
Yanjie Wang ◽  
Yingjie Zhang ◽  
Hongyu Cheng ◽  
Zhicong Ni ◽  
Ying Wang ◽  
...  

Lithium metal batteries have achieved large-scale application, but still have limitations such as poor safety performance and high cost, and limited lithium resources limit the production of lithium batteries. The construction of these devices is also hampered by limited lithium supplies. Therefore, it is particularly important to find alternative metals for lithium replacement. Sodium has the properties of rich in content, low cost and ability to provide high voltage, which makes it an ideal substitute for lithium. Sulfur-based materials have attributes of high energy density, high theoretical specific capacity and are easily oxidized. They may be used as cathodes matched with sodium anodes to form a sodium-sulfur battery. Traditional sodium-sulfur batteries are used at a temperature of about 300 °C. In order to solve problems associated with flammability, explosiveness and energy loss caused by high-temperature use conditions, most research is now focused on the development of room temperature sodium-sulfur batteries. Regardless of safety performance or energy storage performance, room temperature sodium-sulfur batteries have great potential as next-generation secondary batteries. This article summarizes the working principle and existing problems for room temperature sodium-sulfur battery, and summarizes the methods necessary to solve key scientific problems to improve the comprehensive energy storage performance of sodium-sulfur battery from four aspects: cathode, anode, electrolyte and separator.


Nanoscale ◽  
2021 ◽  
Vol 13 (37) ◽  
pp. 15781-15788
Author(s):  
Liaona She ◽  
Feng Zhang ◽  
Congying Jia ◽  
Liping Kang ◽  
Qi Li ◽  
...  

Ti2Nb2O9/CNF anode with excellent sodium storage performance is fabricated by electrospinning and carbonization treatment. The assembled Ti2Nb2O9/CNF//AC SIC exhibits a high energy density of 129 W h kg-1 at 75 W kg-1.


2018 ◽  
Vol 10 (8) ◽  
pp. 2660 ◽  
Author(s):  
Yi Yuan ◽  
Yingjie Li ◽  
Jianli Zhao

The intermittent and inconsistent nature of some renewable energy, such as solar and wind, means the corresponding plants are unable to operate continuously. Thermochemical energy storage (TES) is an essential way to solve this problem. Due to the advantages of cheap price, high energy density, and ease to scaling, CaO-based material is thought as one of the most promising storage mediums for TES. In this paper, TES based on various cycles, such as CaO/CaCO3 cycles, CaO/Ca(OH)2 cycles, and coupling of CaO/Ca(OH)2 and CaO/CaCO3 cycles, were reviewed. The energy storage performances of CaO-based materials, as well as the modification approaches to improve their performance, were critically reviewed. The natural CaO-based materials for CaO/Ca(OH)2 TES experienced the multiple hydration/dehydration cycles tend to suffer from severe sintering which leads to the low activity and structural stability. It is found that higher dehydration temperature, lower initial sample temperature of the hydration reaction, higher vapor pressure in the hydration reactor, and the use of circulating fluidized bed (CFB) reactors all can improve the energy storage performance of CaO-based materials. In addition, the energy storage performance of CaO-based materials for CaO/Ca(OH)2 TES can be effectively improved by the various modification methods. The additions of Al2O3, Na2Si3O7, and nanoparticles of nano-SiO2 can improve the structural stabilities of CaO-based materials, while the addition of LiOH can improve the reactivities of CaO-based materials. This paper is devoted to a critical review on the development on thermochemical energy storage based on CaO-based materials in the recent years.


MRS Advances ◽  
2018 ◽  
Vol 3 (60) ◽  
pp. 3501-3506 ◽  
Author(s):  
Gaind P. Pandey ◽  
Joshua Adkins ◽  
Lamartine Meda

ABSTRACTLithium sulfide (Li2S) is one of the most attractive cathode materials for high energy density lithium batteries as it has a high theoretical capacity of 1166 mA h g-1. However, Li2S suffers from poor rate performance and short cycle life due to its insulating nature and polysulfide shuttle during cycling. In this work, we report a facile and viable approach to address these issues. We propose a method to synthesize a Li2S based nanocomposite cathode material by dissolving Li2S as the active material, polyvinylpyrrolidone (PVP) as the carbon precursor, and graphene oxide (GO) as a matrix to enhance the conductivity, followed by a co-precipitation and high-temperature carbonization process. The Li2S/rGO cathode yields an exceptionally high initial capacity of 817 mAh g-1 based on Li2S mass at C/20 rate and also shows a good cycling performance. The carbon-coated Li2S/rGO cathode demonstrates the capability of robust core-shell nanostructures for different rates and improved capacity retention, revealing carbon coated Li2S/rGO composites as an outstanding system for high-performance lithium-sulfur batteries.


2020 ◽  
Vol 8 (42) ◽  
pp. 14910-14918
Author(s):  
Pingan Yang ◽  
Lili Li ◽  
Hongbin Yuan ◽  
Fei Wen ◽  
Peng Zheng ◽  
...  

A new lead-free antiferroelectric ceramic NBT–SBT was introduced into PVDF polymer to fabricate composites films, achieving record-high energy density of 15.3 J cm−3 at 500 MV m−1 and meeting the requirement of miniaturization and lightweight device.


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