Multi-scale MXene Architectures Bridged by Sodium Sulphate for Low-reflection Terahertz Shielding

doi:10.15541/jim20260352

Abstract

Abstract: Electromagnetic interference (EMI) shielding materials for sixth-generation (6G) terahertz-band communication require both high shielding effectiveness and electrical insulation. However, conventional reflective materials are unsuitable due to signal crosstalk and short-circuit hazards. Based on microcapacitor theory, hierarchical centrifugation was adopted in this study to prepare two types of Ti₃C₂T_xMXene nanosheets with average lateral sizes of 784 nm and 13.39 μm, respectively. Sodium sulfate was introduced as a bridging agent to construct a multiscale microcapacitor network (PNMM). The effects of MXene flake size on the composite film microstructure, insulation performance, and shielding properties in the 0.2-2.0 THz band were systematically investigated. Results show that large-size MXene films (conductivity: 3254.38 S/cm) exhibit reflection-dominated shielding due to severe impedance mismatch (reflectivity: 0.53). By contrast, small-size system, despite possessing abundant interfacial polarization sites, are restricted by limited single-sheet capacitance, leading to a low total shielding effectiveness of merely 8.27 dB. Notably, the sodium sulfate-bridged multiscale network synergistically combines the strong induced-current loss of large plates with the high-density interfacial polarization of small plates, while the bridged interfaces contribute additional Maxwell-Wagner polarization loss. The optimized composite film achieves a total shielding effectiveness of 89.62 dB and an absorptance of 0.77, while maintaining excellent electrical insulation (volume resistivity: 1.72×10⁹ Ω·cm). The absorption loss accounting for over 98% of the total shielding effectiveness, thereby realizing the ideal shielding mode "low reflection, high absorption". This work reveals the synergistic mechanism by which MXene lateral size and interfacial bridging govern microcapacitor network densification and terahertz electromagnetic dissipation, providing experimental evidence and design strategies for developing high-performance, absorption-dominated terahertz shielding materials.

Key words: MXene, electromagnetic shielding, terahertz, size effect, microcapacitors, absorption-dominated mechanism

CLC Number:

TB34
TB332

LI Siyue, FANG Jiangyu, ZUO Peiyuan, ZHUANG Qixin. Multi-scale MXene Architectures Bridged by Sodium Sulphate for Low-reflection Terahertz Shielding[J]. Journal of Inorganic Materials, DOI: 10.15541/jim20260352.

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