COMPOSITE STRUCTURES
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2025
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IF 7.1
Xinyi Ju,Chao Wang,Xueliang Jiang,Feng You,Wei Zhu,Chenjian Li,Chu Yao
The porous composites are positive for noise and electromagnetic wave shielding. Favorable microstructure is the key for realization of noise and electromagnetic co-shielding. Thus, the new method for CNT modification by the carboxylation and silver plating were developed in this study, and the modified CNT and polyimide (PI) were successfully fabricated into conductive aerogels. The modified CNT can effectively regulate the pore structure and conductive network through the interfacial reaction between carboxylation in CNT and polyamide acid. Attributed to a suitable pore structure and three-dimensional conductive network, the PI/CNT composite aerogel simultaneously achieved a sound absorption coefficient of 0.9 in 6000 Hz and an electromagnetic shielding effect of 28 dB in the X band through the absorbing mechanism. The satisfactory electromagnetic and sound shielding were integrated with the PI/CNT composite aerogel, representing a wider prospect of application in electronic and communicating equipment.
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Surfaces and Interfaces
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2025
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IF 6.3
Kunli Chen,Shijie Guo,Shumeng Wang,Yanyan Guo,Jiang Zhao
The development of flexible and wearable electronics necessitates miniaturized energy storage systems with high performance. Spatial constraints are addressed by in-plane micro-supercapacitors (MSCs) via their planar architectures, yet progress is hampered by limitations in electrode materials. A single-step laser direct writing approach is reported here to fabricate nitrogen-doped laser-induced graphene (NLIG) electrodes from modified polyimide (PI) precursors. In situ nitrogen doping is achieved during laser carbonization by utilizing polyimide synthesized from poly(amic acid) containing homogeneously pre-dispersed, nitrogen-rich 1,10-phenanthroline. A three-dimensional (3D) porous architecture is exhibited by the resultant NLIG, with significantly enhanced wettability and optimized electronic structure. These features underpin the MSCs' high areal capacitance (8.81 mF·cm⁻² at 0.5 mA·cm⁻²), excellent cycling stability, and robust mechanical flexibility. Electrochemical performance metrics are maintained across both individual devices and integrated configurations. This scalable methodology for producing NLIG electrodes presents a promising, potentially cost-effective route towards high-performance flexible energy storage solutions crucial for next-generation wearable and portable electronic systems.
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ACS Applied Materials & Interfaces
·
2025
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IF 8.2
Wen-Rui Li,Xiong Yang,Guang-Yu Sun,Yu-Cheng Zhang,Hao-Yan Liu,Xiao-Gang Qin,Bai-Peng Song,Guan-Jun Zhang
Improving the surface insulation strength of substrate material polyimide (PI) is an effective strategy to suppress charging and discharging effects of spacecraft solar arrays. To meet the insulation requirements of next-generation spacecraft with higher voltage levels, the surface insulation of PI must be further improved. Herein, we propose an approach to control the surface roughness and pore distribution of PI using a pore-forming agent. Modulating surface roughness and pore distribution effectively suppresses secondary electron emission avalanches, greatly enhancing surface insulation strength. When the pore-forming agent addition ratio is 50%, the film features the highest flashover threshold of 55.93 kV, a 201.7% improvement over the PI films currently used in spacecraft. The maximum secondary electron yield decreased from 2.01 to 1.32. Additionally, this novel porous PI film is exceptionally lightweight and possesses excellent electrical and thermal properties. The thermal equilibrium temperature is up to 13.44% lower than that of PI films currently used in spacecraft. Even after high- and low-temperature thermal shock, its mechanical properties and flashover performance remain highly stable. The novel polyimide films hold great potential for future applications in insulation of space solar arrays.
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高影响因子
Journal of Materials Research and Technology-JMR&T
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2025
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IF 6.6
Guowei Hou,Yunpeng Zhang,Li Zhang,Guan Wang,Yiwei Wang
Polyimide (PI) is widely used as interturn insulation in solid-state transformers (SSTs) for its corona resistance, but its low thermal conductivity and high dielectric loss cause performance degradation under long-term high-frequency electrothermal stress. Adopting multi-dimensional modification design is an effective solution. In this paper, single-dimensional aluminum nitride (AlN) and multi-dimensional aluminum nitride and boron nitride (AlN-BN) modified PI composites were prepared. The surface of the filler was modified by polydopamine (PDA) and the KH550 silane coupling agent. Through microstructural analysis, thermal and mechanical characterization and high-frequency insulation testing, the enhancement mechanism of high-frequency insulation by the multi-dimensional modification was revealed from the aspects of thermal conductivity, dielectric properties, electrical conductivity and trap characteristics. The results show that the AlN-BN/PI composites exhibits enhancements in thermal conductivity, mechanical properties and high-frequency insulation performance. At 10 wt%, the thermal conductivity of AlN-BN/PI composites increases to 0.311 W/(m·K) (85.12% higher than pure PI and 26.42% higher than AlN/PI). Under 3 kV/20 kHz, the 10 wt% AlN-BN/PI composites achieves a corona aging lifetime of 69.12 min, (372% higher than pure PI and 42% higher than AlN/PI). The enhanced insulation performance of the multi-dimensional composites is attributed to: 1) the AlN-BN "sphere–sheet wrapping" structure constructs a thermal conduction network and mitigates dielectric mismatch and loss; 2) multi-dimensional modification enhances charge dynamics through elevated conductivity and shallow trap density, effectively suppressing electric field distortion. These findings advance insulation system optimization for solid-state transformers.
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DIAMOND AND RELATED MATERIALS
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2025
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IF 5.1
Jintao Huang,Xinfei Zeng,Wentao Yu,Haichen Zhang,Yonggang Min
Electromagnetic wave (EMW) absorption materials play a unique role in both civilian and military domains, hence the creation of high-performance EMW absorbing materials that are “light, thin, broad, and strong” is of significant importance. In this study, we introduced nanoscale nickel metal into the precursor solution during the polymerization phase via in-situ polymerization, and then combined phase separation and high-temperature pyrolysis to prepare polyimide-based porous carbon (PIC)/Ni nano-particles composite (PIC/Ni). The experimental outcomes demonstrate that the introduction of Ni nano-particles, which bring about magnetic loss, has improved the narrow effective absorption bandwidth of the single PIC EMW absorbing material. By controlling the carbonization temperature, it was found that PIC/Ni-700 has a strong capability for EMW loss. Moreover, at a thickness of 4.21 mm, the PIC/Ni-700 exhibits the strongest EMW loss capability at a frequency of 6.16 GHz, recording a minimum reflection loss (RL) of −39.41 dB. PIC/Ni-700 demonstrates effective absorption bandwidth (EABW) of 5.20 GHz (2.0 mm) and 4.16 GHz (2.5 mm), showcasing its characteristic of broadband absorption.
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INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
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2024
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IF 7.7
Jiawei Chen,Kang Ma,Xin Song,Jian Wang,Jianmin Zhang
Polyimide membranes have long been of great interest in the battery industries due to their outstanding thermal stability and flame retardancy. However, the preparation of polyimide membranes with ideal pore structure and excellent lithium-ion transference remains a challenge. In this study, we reported for the first time, that a nano-porous fluorinated and partially carboxylated polyimide/cellulose composite membrane was successfully synthesized by selected monomers and prepared by thermal imidization, phase separation, and alkaline hydrolysis method. Particularly, an appropriate addition of cellulose acetate (CA) during the synthesis process can optimize the pore structure of the membrane. Besides, CA was converted to cellulose after alkaline hydrolysis, further enhancing the electrolyte affinity and lithium-ion transference of the membrane. Hence, this composite membrane exhibited distinct heat-resistance, high porosity (78 %), electrolyte absorption (344 %), and lithium-ion transfer number (0.84). Most importantly, thanks to the above characteristics of the membrane, the assembled LiFePO 4 /Li cells demonstrated excellent cycling stability compared with the cell with PP membrane, showing a capacity retention rate of as high as 93 % after 500 cycles at 1C. We anticipate that this composite membrane with superior physical and electrochemical properties would shed light on the development of next-generation membranes for high-power and high-safety batteries.
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CHEMICAL ENGINEERING JOURNAL
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2024
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IF 13.3
Feilong Shi,Xin Wei,Xiaoqing Wu
The output performance of triboelectric nanogenerators (TENGs) can drop dramatically in high temperature environments because of the thermionic emission effect. To enhance the thermal charge stability and expand the working temperature of TENG, polyimide nanofibers (PINF) were synergistically enhanced by the electron trapping mechanism of reduced graphene oxide (rGO) and interfacial polarization of TiO 2 . With the multiple enhancement effect of polyimide/rGO/TiO 2 composite nanofibers (PRTNF) on triboelectric output, PRTNF-TENG generated an open circuit voltage of 228.26 V and a short circuit current of 5.22 μA, which were 3.80 and 3.48 times higher than those of PINF-TENG. The effective output of polymer-based TENG was investigated from 25 − 300 °C. Compared to room temperature, the PRTNF-TENG can maintain 19.45 % (44.39 V) and 18.20 % (0.95 μA) of the voltage and current at 300 °C, respectively, and still drive 50 commercial LEDs. Furthermore, PRTNF-TENGs were applied as self-powered sensors for firefighters to provide real-time motion monitoring and ambient temperature detection. This PRTNF-TENG has broad application prospects for energy harvesting and smart electronic monitor in harsh environments such as fire and space.
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POLYMER
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2024
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IF 4.1
Cuiqing Zhou,Long Ni,Junyu Lu,Haichao Meng,Yinfu Luo,Mei Liang,Huawei Zou
The development of efficient and multifunctional broadband microwave absorption (MA) materials is critical for military applications to cope with complex environments. Herein, polyimide (PI)/carbon nanotube (CNT) composite foams (PCCFs) were successfully fabricated by assembling CNT with PI via the microsphere foaming method, where gradient CNT allowed tunable electromagnetic parameters. Benefiting from the improved the impedance matching characteristics and microwave dissipation, PCCFs displayed a remarkable reflection loss value of −53.5 dB and an EAB that could be extended up to 13.5 GHz through thickness variation, encompassing almost all C, X and Ku bands. Furthermore, the composite foams exhibited outstanding mechanical property with a specific compressive strength up to 6.8 MPa/(g/cm 3 ), as well as low thermal conductivity (0.106 W/(m·K)) and excellent heat resistance, which are important references for the development of high-performance MA structural components for applications in extreme environments.
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ACS Applied Materials & Interfaces
·
2024
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IF 8.3
Jia Chen,Zhilin Chen,Xianbo Hou,Liming Chen
Efficient thermal insulators that can maintain their efficacy at extreme temperatures are in pressing demand, particularly in fields such as energy saving, aerospace, and sophisticated equipment. Herein, a novel and facile polymerization-regulated optimal strategy is adapted to realize the comprehensive performance of polyimide (PI) aerogel membranes with mechanical robustness, high flexibility, hydrophobicity, light transmittance, and efficient thermal insulation. Benefiting from the hydrolysis of monomers and chemical imidization reaction process verified by a thermo-chemo-mechanically coupled theoretical model, the viscosity of precursors, shrinkage rate, and microstructure of aerogels are precisely controlled, leading to a low thermal conductivity range of 0.023–0.044 W/(m·K). The fabricated PI aerogel membranes, which undergo a remarkable transformation from their initial brittle and opaque nature to a state of high flexibility and transparency, exhibit a 3.0 times increase in tensile strength (4.6 MPa) and a 8.4 times improvement in elongation at break (20.6%) over previous studies while demonstrating an exceptional light transmittance of 92.5% across a wide spectral range from 500 to 2500 nm. Additionally, the PI aerogel membranes possess superior mechanical properties and a wide temperature resistance range extending from −196 to 300 °C. These flexible PI aerogel membranes can be effectively adjusted to meet the practical application of a circular ring solar thermal collector, which displayed a high solar heat collection temperature of 135 °C at a thickness of 0.5 mm. The coordination between the thermophysical properties and mechanical properties of the PI aerogel membranes in this work holds great promise for application requirements of thermal insulators in optical elements under harsh environments.
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POLYMER
·
2024
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IF 4.1
Zhongli Zhang,Zhensheng Wu,Fan Zou,Fuqiang Tian
Polyimide (PI) refers to a polymer containing an imide ring characteristic structure on the main chain. It has excellent thermal stability, insulation properties and other characteristics. The Tesla transformer is the core component of the primary pulse source of the high-current electron beam accelerator. It is also an essential component of the energy storage pulse power supply. Therefore, it has broad application prospects in the fields of national defense and civil industry. If the insulation performance of the turn-to-turn coils of the Tesla transformer does not meet the standards, it will break down during high-voltage corona discharge, causing transformer failure. Therefore, it is crucial to improve the insulation performance of Tesla transformer inter-turn wrapping materials. The incorporation of fluorine-containing groups has proven to be a transformative strategy that significantly enhances the physical, chemical, optical, and electrical properties of PI films. In addition, numerous studies have demonstrated that introducing inorganic fillers into the polyimide matrix can substantially enhance the insulating properties of polyimide films. This paper specifically concentrates on elevating the insulating and thermal attributes of polyimide. Initially, a range of polyimide films was synthesized for performance assessment by employing various fluorinated dianhydride and diamine components, utilizing them as substrates. Then, we used nano-silicon nitride (nano-Si 3 N 4 ) and nano-alumina (nano-Al 2 O 3 ) as doping phases to prepare PI composite films, which reduced the dielectric constant and increased the breakdown strength.
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Journal of Materials Chemistry A
·
2025
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IF 9.5
Mohamed A. Elnaggar,Nanxi Dong,Yongjun Kang,Bingxue Liu,Daolei Lin,Guofeng Tian,Shengli Qi,Dezhen Wu
Polyimide cathode materials have enticed tremendous attention as alternatives to transition-metal electrodes owing to their large theoretical capacity, structural diversity, low cost, and rapid reaction kinetics. Conversely, such imide electrodes still face a severe challenge to achieve their energy storage applications satisfactorily due to the insufficient utilization of their redox-active sites originating from their low electronic conductivities. Herein, four functionalized polyimide composites have been fabricated by virtue of an in situ polycondensation reaction between a newly synthesized benzophenone–benzoquinone-based diamine and commercial dianhydrides in the presence of a conductive Super C45 material for application as cathode materials in Li-ion batteries. Such innovative integration of carbonyl groups of benzophenone, benzoquinone, and diimide rings with the Super C45 material not only creates a stable porous structure with abundant accessible redox-active sites but also guarantees fast electron/ion diffusion. Consequently, our targeted PMQP-SP cathode delivers high capacities of 143 mA h g−1 at 0.2C and 122 mA h g−1 at 1C and attains better rate capability besides ultra-stable cycling performance with 85% capacity retention over 500 cycles at 2C. According to DFT calculations, the theoretical results are well consistent with the electrochemical performance of the synthesized composites. Generally, this work suggests an efficient strategy to design novel carbonyl-rich organic electrodes for next-generation green rechargeable batteries.
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LANGMUIR
·
2024
·
IF 3.7
Luyi Xiao,Yu Yuan,Wei Ding,Yong Wang,Li-Ping Lv
Covalent organic frameworks (COFs) possessing a well-defined structure and abundant functional groups are prospective pseudocapacitive electrode materials. However, their intrinsic poor electrical conductivity and stacking problems usually impede the utilization of their active sites. Herein, we conduct an in situ growth of polyimide COFs (donated as NTDA COFs) enriched with carbonyl groups on multiwalled carbon nanotubes (MWCNTs). An impressive capacitance of 467 F g–1 at 1 A g–1 is achieved for the as-prepared NTDA/MWCNTs composite, significantly surpassing both the pure MWCNTs (60.3 F g–1) and NTDA COFs (284.4 F g–1). No decay of capacitance is observed after 10,000 cycles at 10 A g–1. The assembled device NTDA/MWCNTs//activated carbon reaches a high energy density of 17 Wh kg–1 at 750 W kg–1 while keeping superior charging/discharging stability of 89.5% after cycling for 19,000 times at 10 A g–1. In situ Fourier transform infrared (in situ FT-IR) tests together with the exploration of electrode kinetics show that the boosted capacitance of NTDA/MWCNTs is mainly donated by the redox reactions of carbonyl groups on NTDA COFs, which is largely activated by MWCNTs.
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