Due to the necessity of percolating network, field grading composites filled by particulate fillers usually involve high filler content which can be unfavorable for mechanical properties. Adopting high-aspect-ratio fillers is a feasible strategy of achieving low percolation threshold. In this study, a 2-dimensional early transition metal carbide, Ti₃C₂T_x MXene and its oxidized derivatives were adopted as fillers to prepare polyetherimide (PEI) matrix composite films with nonlinear conductive characteristics. The composite films kept insulating at low electric field and their nonlinear conductive behaviors at high electric field were induced by tunneling effect. The Ti₃C₂T_x/PEI composite showed a remarkable nonlinear coefficient of 10.18 at a filler content of only 6 phr and the percolation threshold of this type of composite was only about 2 phr. Nonlinear conductive characteristics of the composites can be readily adjusted by varying the content and oxidation degree of the filler. Dielectric constants of the composites were also enhanced by the fillers at low filler content with the dielectric loss remaining low. This study revealed the ability of Ti₃C₂T_x and its oxidized derivatives to act as fillers of field grading composites, especially for the composites requiring low filler content.

由于渗透网络的必要性，由颗粒填料填充的现场分级复合材料通常涉及高填料含量，这可能不利于机械性能。采用高纵横比填料是实现低渗透阈值的可行策略。在这项研究中，采用二维早期过渡金属碳化物、Ti ₃ C ₂ T _x MXene 及其氧化衍生物作为填料制备具有非线性导电特性的聚醚酰亚胺（PEI）基复合薄膜。复合薄膜在低电场下保持绝缘，在高电场下的非线性导电行为是由隧道效应引起的。Ti ₃ C ₂ T _x/PEI 复合材料在填料含量仅为 6 phr 时表现出显着的 10.18 非线性系数，并且此类复合材料的渗透阈值仅为约 2 phr。通过改变填料的含量和氧化程度，可以很容易地调整复合材料的非线性导电特性。低填料含量的填料也提高了复合材料的介电常数，同时保持低介电损耗。该研究揭示了 Ti ₃ C ₂ T _x及其氧化衍生物作为现场分级复合材料的填料的能力，特别是对于需要低填料含量的复合材料。