In this study, rod-like TiO 2 filler was synthesized one-step hydrothermal method and was incorporated into P(VDF-TrFE-CFE) polymer matrix to obtain composites with high dielectric constant. It is found that the morphology and content of TiO 2 fillers play a vital role in tailoring the performance of the as-fabricated composites. The rod-like TiO 2 assembled by numerous nanoparticles maintained its primary shape and homogenously distributed in the matrix, thus achieved sophisticated interface and strong interfacial adhesion with P(VDF-TrFE-CFE) polymer, which together contributed to a dramatic improvement in permittivity of composites. Typically, the dielectric constant of composite with 10 vol% rod-like TiO 2 reaches 160 at 100 Hz, in contrast to 102.5 for the composite with 10 vol% commercial TiO 2 and 47 for pristine P(VDF-TrFE-CFE). This study provides a solution for obtaining high-k dielectric composites with low dielectric loss, which is highly desired for advanced electronic devices.
Polymer dielectric materials are highly desirable in electronic devices. However, neither low nor high dielectric constant polymers could meet the requirement of high energy storage application due to the contradiction between dielectric constant and breakdown strength. Herein, in order to obtain high performance polymer dielectrics, poly(vinylidene fluoride-trifluoroethylene-chlorofluoroethylene) (P(VDF-TrFE-CFE)) is filled, as a functional material, into polyurea (PUA) matrix to form all-organic composites. Fortunately, PUA/P(VDF-TrFE-CFE) composites exhibit excellent performance with high dielectric constant and maintain high breakdown strength, resulting in enhanced energy storage density. The breakdown strength of composite film increases to 5130 kV cm−1, and the energy storage density can reach 4.3 J cm−3, which is much higher than pure PUA (2.4 J cm−3) and commercially biaxially oriented polypropylene (BOPP, 1.2 J cm−3). The enhancement of energy density of composite films is mainly attributed to the dipole interaction between PUA and P(VDF-TrFE-CFE) chains, which leads to increases of dielectric constant and maintain high breakdown strength simultaneously. This work provides an effective route to improve the energy density of linear dielectrics and showing great application potential for energy storage.
Electrochromic devices (ECDs) offer significant energy-saving potential for applications such as smart windows and displays by modulating optical properties in response to electrical stimuli. However, their widespread adoption is limited by challenges associated with electrolyte stability and the formation of a robust solid-electrolyte interphase (SEI). In this study, a novel quasi-solid polymer electrolyte (QSPE) based on a UV-curable matrix of poly(ethylene glycol) diacrylate (PEGDA) incorporated with poly(vinylidene fluoride-trifluoroethylene-chlorofluoroethylene) [P(VDF-TrFE-CFE), abbreviated as PVTC] is presented. The high dielectric constant of PVTC facilitates lithium-ion transport, while electrochemical cycling triggers partial dehydrofluorination, thereby promoting in situ formation of a LiF-rich SEI layer on WO 3 surface. The optimized electrolyte exhibits excellent properties, including high optical transparency (88.7%), ionic conductivity (1.76 mS cm −1 ), and mechanical robustness. When applied in ECDs, PVTC enables outstanding performance, achieving 86.29% optical retention from the 5000th to the 40 000th cycle and 98.78% charge retention after 50 000 charge–discharge cycles. Furthermore, prototype demonstrations in smart windows and electrochromic sunglasses validate the scalability and flexibility of the proposed system, highlighting a promising strategy for advancing durable, high-performance ECDs through innovative electrolyte design.
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