In recent years, random metacomposites with tunable negative permittivity have aroused widespread attention because of their distinctive properties and broad potential prospects. It is indicated that an enormously negative permittivity with a large value is not conducive to performance optimizing and impedance matching. In this article, the 2D Mxene Ti₃C₂T_x was selected as the conductive phase instead of metal and carbon materials to fabricate Ti₃C₂T_x/poly(vinylidene fluoride) metacomposites. The results of dielectric properties indicated that the conductive Ti₃C₂T_x networks were formed by Ti₃C₂T_x contacting with each other near the percolation threshold (ƒ_c). The as‐obtained metacomposites containing 75 wt% Ti₃C₂T_x generated percolating phenomenon. Additionally, when the fraction of Ti₃C₂T_x was below ƒ_c, the frequency dispersion behaviors of conductivity were in accordance with the Jonscher's power law, which proved that conducting mechanism was dependent on hopping conduction. While above ƒ_c, the conductivity conformed to the Drude model and Lorentz model, which demonstrated a conductive behavior. Furthermore, the real part of permittivity transformed to negative value at 75 wt%, which can be explained as the existence of the low‐frequency plasma oscillation and electric‐dipole‐induced resonance. The dielectric loss of the metacomposite was also analyzed by the imaginary permittivity spectra. Small negative permittivity values in the range of −550 to −400 were observed, owing to the low free carrier concentration in composites. The appearance of weakly negative permittivity opened up a new direction in negative dielectric materials by 2D layered Ti₃C₂T_x nanomaterials.

中文翻译：

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具有弱负介电常数的二维Ti3C2Tx /聚偏二氟乙烯复合材料

近年来，具有可调的负介电常数的随机复合材料由于其独特的性能和广阔的前景而引起了广泛的关注。可以看出，介电常数大而值较大，不利于性能优化和阻抗匹配。在本文中，选择二维Mxene Ti ₃ C ₂ T _x代替金属和碳材料作为导电相，以制造Ti ₃ C ₂ T _x /聚偏二氟乙烯复合材料。介电性能的结果表明，导电的Ti ₃ C ₂ T _x网络是由Ti ₃形成的。c ^ ₂ Ť _X彼此接近渗透阈值（ƒ接触_Ç）。如此获得的含有75 wt％Ti ₃ C ₂ T _x的超复合材料会产生渗滤现象。此外，在Ti的分数₃ Ç ₂ Ť _X低于ƒ _Ç，电导率的频率分散行为是根据Jonscher的幂定律，这证明了导电机理是依赖于跳跃传导。虽然上面ƒ _Ç，电导率符合Drude模型和Lorentz模型，证明了其导电性能。此外，介电常数的实部在75 wt％时转换为负值，这可以解释为存在低频等离子体振荡和电偶极子引起的共振。还通过虚电容率谱分析了超复合材料的介电损耗。由于复合物中自由载流子的浓度较低，因此观察到的负介电常数在-550至-400范围内。负介电常数的出现为二维层状Ti ₃ C ₂ T _x纳米材料在负介电材料中开辟了新的方向。