Key Takeaways & Executive Findings
- •• The layered arrangement and gradient distribution of magnetic MXene are firstly combined to improve the electromagnetic wave (EMW) RLmin and broaden effective absorption bandwidth. • Absorption, reflection, and transmission (A–R–T) power coefficient analysis is firstly used to guide the gradient distribution, so as to realize EMW incidence at low-concentration surface, loss at middle concentration interlayer and reflection at high-concentration bottom. • The layered gradient composite (LG5-10-15) achieves complete absorption coverage of X-band at thickness of 2.00-2.20 mm with RLmin of -68.67 dB. • The work confirms the importance of layered gradient structure in improving absorption performance and broadens the design of high-performance microwave absorption materials.
Abstract
The morphological distribution of absorbent in composites is equally important with absorbents for the overall electromagnetic properties, but it is often ignored. Herein, a comprehensive consideration including electromagnetic component regulation, layered arrangement structure, and gradient concentration distribution was used to optimize impedance matching and enhance electromagnetic loss. On the microscale, the incorporation of magnetic Ni nanoparticles into MXene nanosheets (Ni@MXene) endows suitable intrinsic permittivity and permeability. On the macroscale, the layered arrangement of Ni@MXene increases the effective interaction area with electromagnetic waves, inducing multiple reflection/scattering effects. On this basis, according to the analysis of absorption, reflection, and transmission (A–R–T) power coefficients of layered composites, the gradient concentration distribution was constructed to realize the impedance matching at low-concentration surface layer, electromagnetic loss at middle concentration interlayer and microwave reflection at high-concentration bottom layer. Consequently, the layered gradient composite (LG5-10–15) achieves complete absorption coverage of X-band at thickness of 2.00–2.20 mm with RLmin of −68.67 dB at 9.85 GHz in 2.05 mm, which is 199.0%, 12.6%, and 50.6% higher than non-layered, layered and layered descending gradient composites, respectively. Therefore, this work confirms the importance of layered gradient structure in improving absorption performance and broadens the design of high-performance microwave absorption materials.
1. Introduction
The widespread use of communication technologies has created a growing demand for electromagnetic wave (EMW) absorbing materials that eliminate undesired electromagnetic radiation and interference, ensuring the appropriate operation of advanced precision equipment [1–3]. In particular, the cutting-edge skins of stealth aircraft, military missiles, and precision instruments also require EMW absorbing materials with integrated multifunctional properties that significantly improve their survivability and combat efficiency on the battlefield [4–6]. It is well known that the microwave absorption performance of the material is determined by the electromagnetic parameters including intrinsic permittivity and permeability, which are mainly dependent on the components and microstructure of absorbents [7, 8]. However, in practical applications such as coatings or hybrid shells, the morphological distribution of the absorbent in carriers also has a significant impact on the overall electromagnetic properties of the coatings or composites and then has an important impact on the EMW absorbing properties [9–11], but it is often ignored.
At present, the various absorbents based on carbon-based materials (graphene, carbon fiber, and carbon nanotubes) [12–14], magnetic-based materials (ferrite, alloys, and metallic oxides) [15–18], and conductive polymers [19, 20] have been developed. Recently, the transition metal carbide/carbon nitride material (MXene) has emerged as ideal candidate for electromagnetic protective materials due to its unique two-dimensional (2D) laminated structure, rich surface polar groups, and adjustable dielectric properties [21–23]. However, the metal-level conductivity derived from the metallic Ti layer on the surface of MXene causes a large amount of EMW reflection; thus, MXene-based materials are typically employed in electromagnetic shielding rather than electromagnetic absorption [24–26]. Fortunately, the incorporation of magnetic components into MXene nanosheets can effectively regulate their dielectric properties to the suitable range for impedance matching and meanwhile endow the magnetic loss ability for broadening the absorption bandwidth, thereby achieving excellent EMW absorbing capabilities. The previous studies have constructed various magnetic heterostructures of MXene/Ni [27], Ni/NC@Ti3C2Tx [28], MXene/NiCo2S4 [29], and MXene@Ni [30], achieving el
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Yang Zhou, Wen Zhang, Dong Pan, Zhaoyang Li, Bing Zhou, Ming Huang, Liwei Mi, Chuntai Liu, Yuezhan Feng, Changyu Shen (2025). Absorption–Reflection–Transmission Power Coefficient Guiding Gradient Distribution of Magnetic MXene in Layered Composites for Electromagnetic Wave Absorption. Nano-Micro Letters. https://doi.org/10.1007/s40820-025-01675-7
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Frequently Asked Questions
What is the main innovation of this study?
The study combines layered arrangement and gradient distribution of magnetic MXene for the first time to improve electromagnetic wave absorption, guided by A–R–T power coefficient analysis.
How does the gradient distribution improve absorption performance?
The gradient distribution realizes impedance matching at the low-concentration surface, electromagnetic loss in the middle concentration interlayer, and microwave reflection at the high-concentration bottom, optimizing overall absorption.
What is the best performance achieved by the layered gradient composite?
The layered gradient composite (LG5-10-15) achieves complete absorption coverage of the X-band at thickness of 2.00–2.20 mm with a minimum reflection loss (RLmin) of -68.67 dB at 9.85 GHz in 2.05 mm.
Why is MXene typically used for shielding rather than absorption?
MXene's high conductivity causes strong reflection of electromagnetic waves, making it more suitable for shielding. Incorporating magnetic components helps regulate dielectric properties for better absorption.
What is the significance of the A–R–T power coefficient analysis?
The A–R–T analysis guides the gradient distribution of absorbents, enabling a rational design that enhances impedance matching and electromagnetic loss, leading to superior absorption performance.
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