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Meng Z, Zhang T, Zhang C, Shang Y, Lei Q, Chi Q. Advances in Polymer Dielectrics with High Energy Storage Performance by Designing Electric Charge Trap Structures. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023:e2310272. [PMID: 38109702 DOI: 10.1002/adma.202310272] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2023] [Revised: 12/06/2023] [Indexed: 12/20/2023]
Abstract
Dielectric capacitors have been developed for nearly a century, and all-polymer film capacitors are currently the most popular. Much effort has been devoted to studying polymer dielectric capacitors and improving their capacitive performance, but their high conductivity and capacitance losses under high electric fields or elevated temperatures are still significant challenges. Although many review articles have reported various strategies to address these problems, to the best of current knowledge, no review article has summarized the recent progress in the high-energy storage performance of polymer-based dielectric films with electric charge trap structures. Therefore, this paper first reviews the charge trap characterization methods for polymeric dielectrics and discusses their strengths and weaknesses. The research progress on the design of charge trap structures in polymer dielectric films, including molecular chain optimization, organic doping, blending modification, inorganic doping, multilayered structures, and the mechanisms of the charge trap-induced enhancement of the capacitive performance of polymers are systematically reviewed. Finally, a summary and outlook on the fundamental theory of charge trap regulation, performance characterization, numerical calculations, and engineering applications are presented. This review provides a valuable reference for improving the insulation and energy storage performance of dielectric capacitive films.
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Affiliation(s)
- Zhaotong Meng
- Key Laboratory of Engineering Dielectrics and Its Application, Ministry of Education, Harbin University of Science and Technology, Harbin, 150080, P. R. China
- School of Electrical and Electronic Engineering, Harbin University of Science and Technology, Harbin, 150080, P. R. China
| | - Tiandong Zhang
- Key Laboratory of Engineering Dielectrics and Its Application, Ministry of Education, Harbin University of Science and Technology, Harbin, 150080, P. R. China
- School of Electrical and Electronic Engineering, Harbin University of Science and Technology, Harbin, 150080, P. R. China
| | - Changhai Zhang
- Key Laboratory of Engineering Dielectrics and Its Application, Ministry of Education, Harbin University of Science and Technology, Harbin, 150080, P. R. China
- School of Electrical and Electronic Engineering, Harbin University of Science and Technology, Harbin, 150080, P. R. China
| | - Yanan Shang
- Key Laboratory of Engineering Dielectrics and Its Application, Ministry of Education, Harbin University of Science and Technology, Harbin, 150080, P. R. China
- School of Electrical and Electronic Engineering, Harbin University of Science and Technology, Harbin, 150080, P. R. China
| | - Qingquan Lei
- Key Laboratory of Engineering Dielectrics and Its Application, Ministry of Education, Harbin University of Science and Technology, Harbin, 150080, P. R. China
- School of Electrical and Electronic Engineering, Harbin University of Science and Technology, Harbin, 150080, P. R. China
| | - Qingguo Chi
- Key Laboratory of Engineering Dielectrics and Its Application, Ministry of Education, Harbin University of Science and Technology, Harbin, 150080, P. R. China
- School of Electrical and Electronic Engineering, Harbin University of Science and Technology, Harbin, 150080, P. R. China
- School of Electrical Engineering, Dalian University of Technology, Dalian, 116024, P. R. China
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Gao JG, Liu LW, Sun WF. Dielectric Characteristics of Crosslinked Polyethylene Modified by Grafting Polar-Group Molecules. Polymers (Basel) 2023; 15:polym15010231. [PMID: 36616579 PMCID: PMC9823466 DOI: 10.3390/polym15010231] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Revised: 12/03/2022] [Accepted: 12/28/2022] [Indexed: 01/03/2023] Open
Abstract
Polar group-modified crosslinked polyethylene (XLPE) materials are developed with a peroxide thermochemical method of individually grafting chloroacetic acid allyl ester (CAAE) and maleic anhydride (MAH) to polyethylene molecular-chains, which are dedicated to ameliorating dielectric characteristics through charge-trapping mechanism. By free radical addition reactions, the CAAE and MAH molecules are successfully grafted to polyethylene molecular chains of XLPE in crosslinking process, as verified by infrared spectroscopy molecular characterizations. Dielectric spectra, electric conductance, and dielectric breakdown strength are tested to evaluate the improved dielectric performances. Charge trap characteristics are investigated by analyzing thermal stimulation depolarization currents in combination with first-principles electronic-structure calculations to reveal the polar-group introduced mechanisms of contributing dipole dielectric polarization, impeding electric conduction, and promoting electrical breakdown field. The grafted polar-group molecules, especially for MAH, can introduce deep-level charge traps in XLPE materials to effectively restrict charge injections and hinder charge carrier transports, which accounts for the significant improvements in electric resistance and dielectric breakdown strength.
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Affiliation(s)
- Jun-Guo Gao
- Key Laboratory of Engineering Dielectrics and Its Application, Ministry of Education, School of Electrical and Electronic Engineering, Harbin University of Science and Technology, Harbin 150080, China
| | - Li-Wei Liu
- Key Laboratory of Engineering Dielectrics and Its Application, Ministry of Education, School of Electrical and Electronic Engineering, Harbin University of Science and Technology, Harbin 150080, China
| | - Wei-Feng Sun
- School of Electrical and Electronic Engineering, Nanyang Technological University, Singapore 639798, Singapore
- Correspondence:
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Water-Tree Characteristics and Its Mechanical Mechanism of Crosslinked Polyethylene Grafted with Polar-Group Molecules. Int J Mol Sci 2022; 23:ijms23169450. [PMID: 36012715 PMCID: PMC9409381 DOI: 10.3390/ijms23169450] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Revised: 08/18/2022] [Accepted: 08/19/2022] [Indexed: 12/02/2022] Open
Abstract
In order to restrain electric-stress impacts of water micro-droplets in insulation defects under alternating current (AC) electric fields in crosslinked polyethylene (XLPE) material, the present study represents chemical graft modifications of introducing chloroacetic acid allyl ester (CAAE) and maleic anhydride (MAH) individually as two specific polar-group molecules into XLPE material with peroxide melting approach. The accelerated water-tree aging experiments are implemented by means of a water-blade electrode to measure the improved water resistance and the affording mechanism of the graft-modified XLPE material in reference to benchmark XLPE. Melting−crystallization process, dynamic viscoelasticity and stress-strain characteristics are tested utilizing differential scanning calorimeter (DSC), dynamic thermomechanical analyzer (DMA) and electronic tension machine, respectively. Water-tree morphology is observed for various aging times to evaluate dimension characteristics in water-tree developing processes. Monte Carlo molecular simulations are performed to calculate free-energy, thermodynamic phase diagram, interaction parameter and mixing energy of binary mixing systems consisting of CAAE or MAH and water molecules to evaluate their thermodynamic miscibility. Water-tree experiments indicate that water-tree resistance to XLPE can be significantly improved by grafting CAAE or MAH, as indicated by reducing the characteristic length of water-trees from 120 to 80 μm. Heterogeneous nucleation centers of polyethylene crystallization are rendered by the grafted polar-group molecules to ameliorate crystalline microstructures, as manifested by crystallinity increment from 33.5 to 36.2, which favors improving water-tree resistance and mechanical performances. The highly hydrophilic nature of CAAE can evidently inhibit water molecules from aggregating into water micro-droplets in amorphous regions between crystal lamellae, thus acquiring a significant promotion in water-tree resistance of CAAE-modified XLPE. In contrast, the grafted MAH molecules can enhance van der Waals forces between polyethylene molecular chains in amorphous regions much greater than the grafted CAAE and simultaneously act as more efficient crystallization nucleation centers to ameliorate crystalline microstructures of XLPE, resulting in a greater improvement (relaxation peak magnitude increases by >10%) of mechanical toughness in amorphous phase, which primarily accounts for water-tree resistance promotion.
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Selvamany P, Varadarajan GS, Chillu N, Sarathi R. Investigation of XLPE Cable Insulation Using Electrical, Thermal and Mechanical Properties, and Aging Level Adopting Machine Learning Techniques. Polymers (Basel) 2022; 14:polym14081614. [PMID: 35458363 PMCID: PMC9033087 DOI: 10.3390/polym14081614] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2022] [Revised: 04/05/2022] [Accepted: 04/13/2022] [Indexed: 02/04/2023] Open
Abstract
Hydrothermal and chemical aging tests on a 230 kV cross-linked polyethylene (XLPE) insulation cable were carried out in the present study to evaluate the degradation and aging levels qualitatively. The samples were subjected to water aging at a temperature of 80 °C, and in an aqueous ionic solution of CuSO4 at room temperature. The diffusion coefficient results indicated that the ion migration was not at the same rate in the aging conditions. The diffusion coefficient–D–of the sample immersed in an aqueous CuSO4 solution was lower than the hydrothermally aged specimens. The hydrophobicity of aged specimens decreased considerably compared to unaged samples. The distribution of trapped charges was quantitatively characterized. The presence of shallow trap energy states were observed in unaged XLPE, whereas the deep trap sites were noticed in aged specimens. In addition, the charge trap characteristics were different for positive and negative charge deposition. Various material characterization techniques, viz. dynamic mechanical analysis (DMA), tensile, contact angle, and LIBS, were further employed on the aged and virgin specimens. The tensile behavior of the hydrothermally aged specimen was degraded due to the oxidised regions, which had formed a weak spot against the mechanical stress. Reduced glass transition temperature and increased loss tangent measurements were noticed for aged specimens over their unaged counterparts. Machine learning techniques, such as the principal component analysis (PCA) and the artificial neural network (ANN) analysis, were performed on LIBS spectral data of the samples to classify the aging mechanisms qualitatively.
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Affiliation(s)
- Priya Selvamany
- Division of High Voltage Engineering, Department of Electrical and Electronics Engineering, College of Engineering, Guindy Campus, Anna University, Chennai 600025, India;
| | - Gowri Sree Varadarajan
- Division of High Voltage Engineering, Department of Electrical and Electronics Engineering, College of Engineering, Guindy Campus, Anna University, Chennai 600025, India;
- Correspondence:
| | - Naresh Chillu
- Department of Electrical Engineering, Indian Institute of Technology Madras, Chennai 600036, India; (N.C.); (R.S.)
| | - Ramanujam Sarathi
- Department of Electrical Engineering, Indian Institute of Technology Madras, Chennai 600036, India; (N.C.); (R.S.)
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Zhang YQ, Wang X, Yu PL, Sun WF. Water-Tree Resistant Characteristics of Crosslinker-Modified-SiO 2/XLPE Nanocomposites. MATERIALS 2021; 14:ma14061398. [PMID: 33805708 PMCID: PMC7998441 DOI: 10.3390/ma14061398] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Revised: 02/25/2021] [Accepted: 03/09/2021] [Indexed: 11/16/2022]
Abstract
Trimethylolpropane triacrylate (TMPTA) as a photoactive crosslinker is grafted onto hydrophobic nanosilica surface through click chemical reactions of mercapto double bonds to prepare the functionalized nanoparticles (TMPTA-s-SiO2), which are used to develop TMPTA-s-SiO2/XLPE nanocomposites with improvements in mechanical strength and electrical resistance. The expedited aging experiments of water-tree growth are performed with a water-knife electrode and analyzed in consistence with the mechanical performances evaluated by means of dynamic thermo-mechanical analysis (DMA) and tensile stress-strain characteristics. Due to the dense cross-linking network of polyethylene molecular chains formed on the TMPTA-modified surfaces of SiO2 nanofillers, TMPTA-s-SiO2 nanofillers are chemically introduced into XLPE matrix to acquire higher crosslinking degree and connection strength in the amorphous regions between polyethylene lamellae, accounting for the higher water-tree resistance and ameliorated mechanical performances, compared with pure XLPE and neat-SiO2/XLPE nanocomposite. Hydrophilic TMPTA molecules grafted on the nano-SiO2 surface can inhibit the condensation of water molecules into water micro-beads at insulation defects, thus attenuating the damage of water micro-beads to polyethylene configurations under alternating electric fields and thus restricting water-tree growth in amorphous regions. The intensified interfaces between TMPTA-s-SiO2 nanofillers and XLPE matrix limit the segment motions of polyethylene molecular chains and resist the diffusion of water molecules in XLPE amorphous regions, which further contributes to the excellent water-tree resistance of TMPTA-s-SiO2/XLPE nanocomposites.
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Affiliation(s)
- Yong-Qi Zhang
- Key Laboratory of Engineering Dielectrics and Its Application, Ministry of Education, School of Electrical and Electronic Engineering, Harbin University of Science and Technology, Harbin 150080, China;
| | - Xuan Wang
- Key Laboratory of Engineering Dielectrics and Its Application, Ministry of Education, School of Electrical and Electronic Engineering, Harbin University of Science and Technology, Harbin 150080, China;
- Correspondence: (X.W.); (W.-F.S.); Tel.: +86-158-4659-2798 (W.-F.S.)
| | - Ping-Lan Yu
- Chaozhou Power Supply Bureau, Guangdong Power Grid Co. Ltd., Chaozhou 521000, China;
| | - Wei-Feng Sun
- Key Laboratory of Engineering Dielectrics and Its Application, Ministry of Education, School of Electrical and Electronic Engineering, Harbin University of Science and Technology, Harbin 150080, China;
- Correspondence: (X.W.); (W.-F.S.); Tel.: +86-158-4659-2798 (W.-F.S.)
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