Zero‐temperature‐coefficient of capacitance in BaTiO 3 / PI composite films using paraffin as barrier layer

Self Cite

In order to prepare polymer dielectric materials with high energy storage density, a series of polyimide (PI) based Janus composite films were prepared by metal–organic frameworks (MOFs) material (UiO‐66) with high dielectric constant (ɛr) and boron nitride nanosheets (BNNSs) with high breakdown strength (Eb). As reported, the UiO‐66 can significantly improve the ɛr of the composites. The ɛr of 20 wt% UiO‐66/PI film is 10.51 at 103 Hz, which is 3.1 times that of pure PI film (3.39 at 103 Hz). However, the Eb of 20 wt% UiO‐66/PI is only 58 MV m−1, which is only 16.51% of pure PI (352 MV m−1). The sharp decline in Eb reduces the energy storage capacity of the composites. To solve this problem, first, BNNSs with an average diameter of 2 μm and a thickness of 1.36 nm (about 4–5 layer) were obtained by hydrothermal reflux stripping. BNNSs/PI//UiO‐66/PI Janus composite films with double‐layer structure were prepared by directly casting BNNSs/PI on the surface of UiO‐66/PI. For 0.3 wt% BNNSs/PI//10 wt% UiO‐66/PI, the calculated energy storage density (Ue) is 5.75 J cm−3 at 140 MV m−1, which is 3.57 times that of pure PI film (1.61 J cm−3 at 140 MV m−1). Meanwhile, the charge discharge efficiency is 82.55% (at 140 MV m−1).Highlights BNNSs prepared by hydrothermal reflux stripping have fewer layers. BNNSs/PI composites improve the Eb of UiO‐66/PI composites by Janus structure. The Ue of BP‐0.3//UP‐10 composites with Janus structure was 5.75 J cm−3.

Section: Dielectric Performance Of Uio-66/pimentioning

confidence: 99%

Janus composite film comprising metal–organic framework/polyimide and BNNSs/polyimide as high energy storage dielectrics

Long,

Qu,

Kang

et al. 2024

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“…Nowadays, it is increasingly urgent to develop integrated capacitors with lightweight, miniaturization, and high electric energy density. [1][2][3] Dielectrics, as the critical part 4 of capacitors, need a high dielectric constant (ε r ), low dielectric loss (tanδ), and high breakdown strength (E b ), 5,6 convenient processing, low density, and so on. 7 Generally, dielectrics composed of a single material cannot possess both high ε r and high E b .…”

Section: Introductionmentioning

confidence: 99%

Ultra‐high power density in poly(arylene ether nitrile)‐based composites containing barium titanate and boron nitride nanosheets

Pu,

Zeng,

Long

et al. 2023

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Barium titanate (BT) nanoparticles were surface coated by a silane coupling agent (KH550) and core–shell structured nanoparticles (named KH550@BT) were obtained. Similarly, BT nanoparticles coated by polydopamine (PDA) were named as PDA@BT. Meanwhile, boron nitride (BN) nanosheets (BNNS) were successfully unstripped from block BN. Then, two kinds of ternary poly(arylene ether nitrile) (PEN)‐based composites are prepared using the solution casting method. Composites with 30 wt% KH550@BT and 12 wt% BNNS were named as KH550@BT/BNNS/PEN. Composites with 30 wt% PDA@BT and 12 wt% BNNS were named as PDA@BT/BNNS/PEN. The microstructure, dielectric properties, and energy storage properties of the ternary composites were studied in detail. PEN embedded with either BNNS or BT were prepared and studied for comparison. As a result, the introduction of BT will improve the dielectric constant (εr) and energy storage density (W), but it will reduce the breakdown strength (Eb) and charge–discharge efficiency (η) of composites. BNNS not only improves Eb and W but also improves η of composites. Although the introduction of BT and BNNS simultaneously may reduce η, it will improve εr, Eb, and W of composites. Most importantly, the fast discharge speed and high power density demonstrate that the BT/BNNS/PEN composites are potential candidates to be used in high power pulsed capacitors fields.Highlights Boron nitride nanosheets improve the breakdown strength of composites. The composites achieve simultaneous increment of εr and Eb. The power density of the BT/BNNS/PEN composites was higher than 70 MW cm−3.

“…[21][22][23] In addition, the incorporation of single or multiple insulating layers on the surface of the dielectric filler can help to balance the band gap between the conductivity of the polymer material and the inorganic filler, suppressing the leakage current at the interface, and thus reduce the dielectric loss of the composite dielectrics. [24][25][26][27][28] As an excellent insulating material, magnesium oxide (MgO), with a dielectric constant of $9.7, has been used to meliorate the dielectric constant difference between BaTiO 3 and polymer matrices. 29,30 Chen et al demonstrated that the P(VDF-HFP) composite with 1 vol% of BaTiO 3 @MgO obtained the maximum energy storage density of 5.6 J/cm 3 , increasing by 55.6% compared to the P(VDF-HFP) composite containing 1 vol% of BaTiO 3 .…”

Section: Introductionmentioning

confidence: 99%

“…Unlike conductive carbon‐based fillers, inorganic fillers like barium titanate (BaTiO 3 ) nanoparticles will not establish conductive pathways that affect the insulation property of matrices even if the content threshold appears 21–23 . In addition, the incorporation of single or multiple insulating layers on the surface of the dielectric filler can help to balance the band gap between the conductivity of the polymer material and the inorganic filler, suppressing the leakage current at the interface, and thus reduce the dielectric loss of the composite dielectrics 24–28 …”

Section: Introductionmentioning

confidence: 99%

Construction of sandwich‐layered polyimide hybrid films containing double core–shell structured fillers for high energy storage density

Cao,

Zhang,

Zhao

et al. 2023

The inherent low dielectric constant of polyimide (PI) dielectrics restricts their applications to become a component of high energy density film capacitors. In this work, double core–shell structured barium titanate@magnesium oxide@polydopamine (BaTiO3@MgO@PDA) nanoparticles were synthesized successfully and utilized as high dielectric constant functional fillers for PIs, in which the insulating MgO layer meliorated dielectric constant difference between BaTiO3 and PI matrix, and the organic PDA layer improved the compatibility between the inorganic fillers and PI matrices. Then, a series of sandwich‐structured PI‐based hybrid films was prepared through a layer‐by‐layer solution casting method. The middle layer of pure PI with excellent insulating properties effectively suppressed charge injection. With the combination of sandwich structure and the BaTiO3@MgO@PDA nanoparticles, the PI hybrid film containing 15 wt% fillers in the outer layers achieved the maximum breakdown strength of 425.68 kV/mm and the maximum energy density of 5.132 J/cm3, which was 68.3% and 413% higher than those of pure PI film, respectively, meanwhile maintained a low dielectric loss value of 0.0083 at 1 kHz. The introduction of BaTiO3@MgO@PDA enhanced the interfacial polarization due to the high barrier energy between adjacent layers preventing the transfer of electrons and weakening the leakage current in the sandwich‐structured composite film. This work demonstrates that an appropriate combination of high dielectric hybrid fillers and multilayer structure can effectively increase the energy storage density of PI substrate for high‐temperature energy storage applications.Highlights The double core–shell structured BaTiO3@MgO@PDA was synthesized successfully. The sandwich‐structured hybrid films were prepared by layer‐by‐layer method. The energy density of hybrid films reached a high value of 5.132 J/cm3.