Inducing multiple polarizations in core@double-shell structured MXene/PVDF flexible nanodielectrics toward elevated overall dielectric performances

Abstract

Titanium carbide (MXene) has garnered much attention in the development of high-permittivity (ε) flexible polymeric dielectrics because of its exceptionally high electrical conductivity; nevertheless, large dielectric loss at the percolating filler loading severely restricts their engineering applications. In this work, the exfoliated MXene was first surface-oxidized (O-MXene) and then encapsulated with a polydopamine (PDA) layer, and the dielectric properties of the O-MXene@PDA/polyvinylidene fluoride (PVDF) nanocomposites were investigated. The findings reveal that compared with both pristine MXene and MXene@PDA, the double-shell O-MXene@PDA imparts PVDF with evidently enhanced ε and breakdown strength (E_b) along with significantly lower dielectric loss. The elevated ε is ascribed to the O-MXene@PDA inducing multiple intra-particle and inter-particle polarizations. The presence of double shells not only induces deep charge traps capturing mobile charges but also raises the energy barrier for trapped charge de-trapping, subsequently leading to remarkably restrained loss and leakage current in the nanocomposites. Moreover, the second PDA interlayer enhances interfacial interactions between MXene and PVDF, and notably mitigates the strong dielectric mismatch between the two components, therefore lessening the formation of electric trees and promoting the E_b. The theoretical fitting and simulations provide deep insights into the underlying multiple polarization mechanisms and the impact of the double shells on charge migration. This core@double-shell approach offers new insights into the fabrication and design of percolating nanocomposites at low filler loading with concurrently high ε and E_b but low loss, presenting potential applications in power electronic devices and power systems.

Keywords

Polymer nanocomposites / core@double-shell structure / charge traps / dielectric properties

References

[1] Liu H,Zhang T.Imidazole diphenyl phosphate-boron nitride nanoflakes for significantly enhancing flame retardation and thermal transport performance of epoxy.J Alloys Compd2025;1020:179414

[2] Zhang M,Zhang Y.Regulating SiO₂ interlayer morphology towards synergistically reinforced dielectric properties and thermal conductivity in Si/PVDF composites.Compos Part A Appl S2025;194:108893

[3] Wang Z,Luo M.Enhancing electrical insulation and thermal conductivity in polymer through constructing energy-dissipation organic electron acceptor/inorganic filler.Small2025;21:e2502696

[4] Luo M,Wang R,Wang Z.Enhanced dielectric breakdown strength and thermal conductivity of silicone gel composites with high-electron-affinity silicon Dioxide/Cationic Polymer/Nano-diamond.Chem Eng J2024;501:157623

[5] Wang Z,Cao X.Dielectric and thermal properties characterisation and evaluation of novel epoxy materials for high-voltage power module packaging.HIGH VOLT2024;9:1021-32

[6] Li B,Manias E.Polarization mechanism underlying strongly enhanced dielectric permittivity in polymer composites with conductive fillers.J Phys Chem C2022;126:7596-604

[7] Sun S,Yang J.Surface modification engineering on polymer materials toward multilevel insulation properties and subsequent dielectric energy storage.Mater Today2024;80:758-823

[8] Yuan M,Li B,Rajagopalan R.Thermally stable low-loss polymer dielectrics enabled by attaching cross-linkable antioxidant to polypropylene.ACS Appl Mater Interfaces2020;12:14154-64

[9] Ren J,Yang J.Significantly enhancing the through-plane thermal conductivity of epoxy dielectrics by constructing aramid nanofiber/boron nitride three-dimensional interconnected framework.J Appl Phys2024;136:045101

[10] Sun W,Peng K.All-organic hyper-crosslinked polymer/polyimide composite films with ultralow high-frequency dielectric constant.Macromol Rapid Commun2023;44:e2200956

[11] Liu G,Chang Z.Significantly enhancing the high-temperature breakdown and capacitive performances of dielectric polymers via incorporating alumina nanotubes as equivalent crosslinking points.Adv Funct Mater2025;35:2425001

[12] Ren Z,Zhu L.Remarkably boosted high-temperature electrostatic energy storage of polyetherimide film induced by TiO₂@Au@AlO_x@Au core-shell nanofibers.Adv Funct Mater2025;35:2417156

[13] Gao F,Xu X.A N/Co co-doped three-dimensional porous carbon as cathode host for advanced lithium-selenium batteries.Rare Met2023;42:2670-8

[14] Zhao D,Yu S.Lychee seed-derived microporous carbon for high-performance sodium-sulfur batteries.Carbon2023;201:864-70

[15] Zhong S,Wang S.Metal-based nanowires in electrical biosensing.Rare Met2024;43:6233-54

[16] Wang X,Zhao H.Polymer-based dielectric composite films with excellent dielectric energy storage and thermal management capabilities.Adv Funct Mater2025;Epub ahead of print:

[17] Chen X,Zhang K.Synergistically depressed dielectric loss and elevated breakdown strength in core@double-shell structured Cu@CuO@MgO/PVDF nanocomposites.Polymer2024;307:127321

[18] Wang F,Zhou J.Engineering of core@double-shell Mo@MoO₃@PS particles in PVDF composites towards improved dielectric performances.J Polym Res2023;30:3494

[19] Wang F,Chen H.Surface-confined winding assembly of SiO₂ on the surface of BaTiO₃ leading to enhanced performance of dielectric nanocomposites.Adv Funct Mater2024;34:2410862

[20] Ma J,Peng Q.Low-temperature induced crystallographic orientation boosting Li storage performance of Na₂ MoO₄ ·2H₂O.Rare Met2025;44:135-46

[21] Zhang M,Cheng Y.Synergistic modulation of free volume and band structure assist the high energy storage performance of polymer dielectrics.Adv Funct Mater2025;35:2506101

[22] Liu Z,Jaye C.Vitreous silica supported metal catalysts for direct non-oxidative methane coupling.Chem Eng J2024;499:156436

[23] Zhang J,Ye X.Ultralight and compressive SiC nanowires aerogel for high-temperature thermal insulation.Rare Met2023;42:3354-63

[24] Wang Z,Yang M.Surface strengthening of polymer composite dielectrics for superior high-temperature capacitive energy storage.Adv Energy Mater2025;15:2405411

[25] Ai D,Han Y.Polymer nanocomposites with concurrently enhanced dielectric constant and breakdown strength at high temperature enabled by rationally designed core-shell structured nanofillers.J Mater Sci Technol2025;210:170-8

[26] Wang H,Wang X.Dielectric properties and energy storage performance of PVDF-based composites with MoS2@MXene nanofiller.Chem Eng J2022;437:135431

[27] Yuan J,Li D,Zhou Y.Epidermal visualized health monitoring system based on stretchable and washable TPU hybrid conductive microtextiles.Rare Met2024;43:3185-93

[28] Wang X,Chen D.BaTiO₃ nanoparticles coated with polyurethane and SiO₂ for enhanced dielectric properties.ACS Appl Nano Mater2023;6:2615-24

[29] Xiao M,Du B.Improving the dielectric properties of polypropylene for metallised film capacitors based on cyclic olefin copolymer blending.IET Nanodielectr2024;7:140-9

[30] Zhang Y,Liu D.AI safety of film capacitors.IET Nanodielectr2024;7:131-9

[31] Wang Y,Zhao L.Preparation of two-dimensional gradient fillers reinforced polymer nanocomposites for high-performance energy storage of dielectric capacitors.J Energy Storage2024;101:113886

[32] Yang Y,Jiang P.Improved dielectric and energy storage properties of three-dimensional BaTiO₃/polyvinyl alcohol-boron nitride flexible dielectric composite via template infiltration strategy.IET Nanodielectr2024;7:68-77

[33] Zhou Y,Qiu S.Microscopic response mechanism of epsilon-negative and epsilon-near-zero metacomposites.Research2025;8:0556 PMCID:PMC11694408

[34] Zhong S,Wang DC.Passive isothermal flexible sensor enabled by smart thermal-regulating aerogels.Adv Mater2025;37:e2415386

[35] Zhou Y,Bai Y,Li K.Rise of flexible high-temperature electronics.Rare Met2023;42:1773-7

[36] Wang R,Huang S.Dielectric polymers with mechanical bonds for high-temperature capacitive energy storage.Nat Mater2025;24:1074-81

[37] Zhou Y,Yin J.Flexible metasurfaces for multifunctional interfaces.ACS Nano2024;18:2685-707

[38] Xing K,Wang XJ.Enhanced energy storage performance of nano-submicron structural dielectric films by suppressed ferroelectric phase aggregation.Nat Commun2025;16:2006 PMCID:PMC11865547

[39] Qu Y,Luo Y.Universal paradigm of ternary metacomposites with tunable epsilon-negative and epsilon-near-zero response for perfect electromagnetic shielding.Rare Met2024;43:796-809

[40] Zhou Y,Xiang S.Unleashing the potential of MXene-based flexible materials for high-performance energy storage devices.Adv Sci2024;11:e2304874 PMCID:PMC10797478

[41] Yin P,Tang Q.Polymer dielectrics intercalated with a non-contiguous granular nanolayer for high-temperature pulsed energy storage.Energy Storage Mater2025;77:104213

[42] Ren Z,Tang Q.Core-shell TiO₂ @Au nanofibers derived from a unique physical coating strategy for excellent capacitive energy storage nanocomposites.Adv Funct Mater2024;34:2401907

[43] Wang G,Li L,Liu J.Self-assembled MXene@fluorographene hybrid for high dielectric constant and low loss ferroelectric polymer composite films.ACS Appl Mater Interfaces2024;16:25268-79

[44] Huang B,Zhao Y.Al@SiO₂ core-shell fillers enhance dielectric properties of silicone composites.ACS Omega2023;8:35275-82 PMCID:PMC10536023

[45] Zhou Y,Cao X.Enhanced thermal conductivity and electrical insulation properties of liquid crystalline epoxy composites by using optimized alumina hybrid fillers.Mater Today Phys2025;54:101719

[46] Zhang F,Wu C,Zhang N.Glutaraldehyde-assisted crosslinking for the preparation of low dielectric loss and high energy density cellulose composites filled with poly(dopamine) modified MXene.Eur Polym J2024;221:113526

[47] Yang K,Liang L,Chen X.Thermal conductivity and dielectric properties of EP composites filled by one-dimensional core-shell structured h-BN@SiO₂ fibers.Ceram Int2024;50:9441-52

[48] Hou D,Chen W,Shen J.Core@double-shell structured fillers for increasing dielectric constant and suppressing dielectric loss of PVDF-based composite films.Ceram Int2022;48:22691-8

[49] Wang H,Zhong S,Dang Z.Enhanced dielectric constant and concurrently suppressed dielectric loss of PVDF composites incorporating BaTiO3@SSCNT@SiO₂ core@double-shell structured fillers.Ceram Int2024;50:26334-42