Lightweight and Highly Heat‐Resistant Microcellular Polyetherimide/Barium Titanate/Carbon Nanotube Nanocomposites with High Dielectric Permittivity and Low Dielectric Loss

Abstract

Dielectric materials can be used to control/ store charge and electric energy, which has important potential application value for the dielectric energy storage and intelligent sensing in areas such as aerospace, electronics, and military engineering. [1,2] The dielectric materials with high dielectric permittivity (ε 0 ) and low dielectric loss (tanδ) are of great significance to national security defense and economic development. [3][4][5][6] Ceramic-based dielectric materials are widely used in electronic components in communication, military, and other related fields due to their extremely high dielectric permittivity. [7][8][9] However, the complex preparation process, high processing temperature, brittleness, and low breakdown strength of ceramics greatly limit their application range. [10] Polymers are the industrial choice of dielectric materials for charge storage applications mainly because of their high breakdown strength and excellent processability. Nevertheless, it is a great challenge that the pure polymers always have a very low dielectric permittivity. [11][12][13] Therefore, the high dielectric composite materials obtained by integrating high dielectric particles and polymers in a certain physical/chemical way have great application prospects. One common approach is to add ceramic fillers such as barium titanate (BaTiO 3 ), barium strontium titanate (Ba x Sr 1-x TiO 3 ), and calcium copper titanate (CaCu 3 Ti 4 O 12 ) to the polymers to improve their dielectric properties. [14][15][16][17] However, a higher dielectric permittivity usually requires a higher loading of ceramic filler, which affects the machinability and mechanical strength of the composites. Another approach is to add conductive fillers such as Cu, Ag, graphene, and carbon nanotubes (CNTs) to the polymers, which can obtain very high dielectric permittivity at a low conductive filler loading. [18][19][20][21][22][23] Unfortunately, the conductive fillers are prone to agglomerate, resulting in excessive leakage current, which will cause the sharp increase in dielectric loss of the conductive filler/polymer composites. In recent years, researchers have been keen to combine

Improved Capacitive Energy Storage Nanocomposites at High Temperature Utilizing Ultralow Loading of Bimetallic MOF

“…However, with the increase of filler content, ZIF‐67 reduces the van der Waals force between molecular chains, and the plasticizing effect on the composite material becomes more and more obvious, thereby reducing T g . [ 44 ] When the ZIF 8–67 content was 0.5 wt%, the T g of the nanocomposite was the highest (263.87 °C). The above results also indicated that the appropriate amount of ZIF 8–67 could help to improve the temperature stability of the nanocomposites.…”

Cetyltrimethylammonium bromide decorated MXene/polyimide nanocomposites with enhanced dielectric properties, thermostability, and moisture resistance

“…On the one hand, the introduction of nano fillers will lead to volume exclusion, which will increase the free volume between molecular chains. On the other hand, if the nano filler has a good interfacial bonding with the molecular chain, it can act as cross‐linking point, so as to limit the movement of the molecular chain and improve the glass transition temperature 33 . It is indicated that MXene@CTAB has good interaction with polyimide molecules and further improves the service temperature of the nanocomposites.…”

Achieving high energy storage in BaTiO3/rGO/PVDF nanocomposites by regulating the charge transfer path at the hetero-interface

“…To address this issue, much research has been conducted from the perspective of interfacial control. The introduction of core–shell structured nanoparticles has been demonstrated to be a viable method, such as BTO@SiO 2 , 15–17 BTO@Al 2 O 3 , 18,19 BTO@TiO 2 , 20–23 SiO 2 @PVDF, 24 BTO@PDA, 25–29 and dopamine@BCZT, 30,31 BTO@TiO 2 /P(VDF-HFP) nanocomposites reported by Nan et al 9 achieved a high U e of 31.2 J cm −3 , which was nearly 15 times as large as that of BOPP. The local electric field concentration and carrier accumulation were suppressed by introducing TiO 2 with a moderate ε r (∼40), achieving the purpose of simultaneously increasing polarization and E b .…”

“…The mechanism is that the charge transfer path is optimized by the insulating shell, which can confine the carriers in the insulating shell layer, making it difficult to form the leakage current and conducting channel. 15,24,25 However, U e of nanocomposites cannot be effectively improved to a large extent due to the low polarization of most insulating shells, such as PVDF and PDA. The enhancement of the polarization and the control of the charge transfer path through reasonable interface design to improve the U e and η have become key problems to be solved.…”