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Abstract Polyvinylidene fluoride (PVDF) is a semicrystalline polymer used in thin‐film dielectric capacitors because of its inherently high dielectric constant and low loss tangent. Its dielectric constant can be increased by the formation and alignment of its β‐phase crystalline structure, which can be facilitated by 2D nanofillers. 2D carbides and nitrides, MXenes, are promising candidates due to their notable dielectric permittivity and ability to increase interfacial polarization. Still, their mixing is challenging due to weak interfacial interactions and poor dispersibility of MXenes in PVDF. This work explores a novel method for delaminating Ti3C2TxMXene directly into organic solvents while maintaining flake size and quality, as well as the use of a non‐solvent‐induced phase separation method for producing both dense and porous PVDF‐MXene composite films. A deeper understanding of dielectric behavior in these composites is reached by examining MXenes with both mixed and pure chlorine terminations in PVDF matrices. Thin‐film capacitors fabricated from these composites display ultrahigh discharge energy density, exceeding 45 J cm−3with 95% efficiency. The PVDF‐MXene composites are also processed using a green and sustainable solvent, propylene carbonate.
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Influence of MXene Interlayer Spacing on the Interaction with Microwave Radiation
Abstract The origin of MXene's excellent electromagnetic shielding performance is not fully understood. MXene films, despite being inhomogeneous at the nanometer scale, are often treated as if they are compared to bulk conductors. It is reasonable to wonder if the treatment of MXene as a homogeneous material remains valid at very small film thickness and if it depends on the interlayer spacing. The goal of the present work is to test if the homogeneous material model is applicable to nanometer‐thin Ti3C2TxMXene films and, if so, to investigate how the model parameters may depend on variations in MXene interlayer spacings. MXene films containing flakes with interlayer spacing between 1.9 and 5.5 Å have been prepared using various intercalating agents. It is shown that modeling the films as being homogeneous agrees with experimental tests in the microwave frequency range. Microwave conductivity and dielectric constant parameters are estimated for the homogeneous film model by fitting measured results. The direct current (DC) conductivity matches the estimated microwave conductivity on the order of magnitude. A highly effective dielectric constant provides a good fit for the lower conductivity MXene films. Optical absorption agrees with the homogeneous material model of thin films as well.
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- Award ID(s):
- 2034114
- PAR ID:
- 10540884
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Advanced Functional Materials
- Volume:
- 35
- Issue:
- 18
- ISSN:
- 1616-301X
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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