In a revolutionary stride to mitigate the pressing issues of electromagnetic (EM) pollution and interference, a groundbreaking research has emerged from a team led by Professors Yang Yang and Wei Lu at Tongji University. The team has pioneered a novel strategy that combines electron localization with the remarkable material known as MXene, specifically Ti₃C₂Tₓ, enhanced with nickel (Ni) nanoclusters. This innovative approach sets a new standard for electromagnetic wave (EMW) absorbers, overcoming traditional limitations around bandwidth, absorption, and material thickness.
As the world embraces the advancements of 5G, the Internet of Things (IoT), and artificial intelligence (AI), the demand for effective solutions to EM wave absorption is more critical than ever. Traditional absorbers have often struggled with various conflicting requirements – achieving a thin profile while ensuring broad absorption bandwidth and strong electromagnetic attenuation. In an inspiring answer to this challenge, the Tongji research team presents their findings in the esteemed journal Nano-Micro Letters, showcasing the potential of Ni-MXene composites to revolutionize how we manage electromagnetic waves.
Electromagnetic wave absorption fundamentally relies on the conversion of EM energy into heat, primarily achieved through either dielectric or magnetic losses. While MXenes, particularly titanium carbide (Ti₃C₂Tₓ), boast impressive metallic conductivity and an expansive surface area, their inherent excessive conductivity can lead to poor impedance matching. This ultimately results in unwelcome reflections of EM waves rather than their absorption. The innovative team addressed this issue with their electron localization strategy, which confines electrons to localized regions to enhance polarization and facilitate effective electromagnetic wave dissipation.
The key to the new electron localization strategy lies within the metal-support interaction (MSI) created by anchoring nickel nanoclusters onto the MXene substrate. This strategic interaction disrupts the symmetrical distribution of electrons across the MXene, confining them into small, localized clusters that act as micro-dipoles. When exposed to alternating EM fields, these confined electrons generate stronger dipole polarization, thereby significantly enhancing average dielectric loss. The presence of these nanoclusters thus transforms the capabilities of MXene from a mere conductive material to a highly effective EM wave absorber.
One of the most distinguishing features of the new Ni-MXene composite is its ability to achieve a remarkable minimum reflection loss (RLₘᵢₙ) of −54 dB, at a thickness of just 2 mm. This performance means that an astonishing 99.999% of incoming EM waves are absorbed by the material—this is a fourfold increase in absorption over pure MXene, which exhibited an RLₘᵢₙ of only −11.9 dB. More impressively, the effective absorption bandwidth (EAB) for the new composite stretches to an impressive 6.8 GHz, ensuring efficient absorption across a considerable range of frequencies critical for modern communication technologies.
The chemical synthesis of these Ni-MXene composites occurs with remarkable precision and scalability. The team begins by preparing MXene through selective etching of the MAX phase Ti₃AlC₂, resulting in Ti₃C₂Tₓ MXene with ample surface vacancies and functional groups—favorable characteristics for anchoring nickel. Following this, they introduce nickel chloride hexahydrate into the MXene matrix and subject the mixture to heat treatment under argon. By meticulously adjusting the nickel precursor concentration, they manage to create various morphologies of nickel anchoring on the MXene that optimally enhance its EM wave absorption properties.
Among the diverse nickel morphologies explored, it was the nickel nanoclusters, roughly between 1 and 2 nm in size, that attained the most significant MSI effect. This ensured that the electron localization and dipole polarization losses were at their optimal levels, substantially increasing EMW dissipation. Conversely, larger nanoparticles yielded excessive electron scattering, diminishing conductivity and polarization impacts, thus underscoring the importance of precise material engineering in the research.
This innovative research not only provides exceptional results in terms of EM wave absorption efficiency but also highlights important dual loss mechanisms. The addition of nickel nanoclusters equips the composite with both dielectric loss—attributed to the MXene—and a magnetic loss component due to the nickel clusters, generating synergistic effects that boost overall absorption capabilities. Advanced characterizations, including X-ray photoelectron spectroscopy and spherical aberration-corrected scanning transmission electron microscopy, validate the strong MSI in the constructs, demonstrating that not only are the nanoclusters uniformly distributed on the MXene, but that the arranged bonds are critical in stabilizing the electron localization and enhancing EM absorption.
When subjected to rigorous evaluations across a frequency spectrum from 2 to 18 GHz—an essential domain for emerging 5G networks and radar technologies—the Ni-MXene composites displayed unparelleled stability and performance. With their remarkable ability to sustain operation over numerous cycles, even when nickel was loaded up to 5 wt%, the samples remained capable of converting significant quantities of EM energy into heat, far surpassing their individual components. The encapsulated design of just 2 mm thickness, in conjunction with the lightweight characteristics mandated by its two-dimensional structure, positions this composite as an ideal candidate for adoption in various flexible and space-limited applications.
In terms of broader implications, this research transcends the realm of EMW absorption, paving possibilities for applications in electromagnetic interference (EMI) shielding. Given that this new composite combines high conductivity and absorption capabilities, it has the potential to substitute conventional heavy metal shielding methods currently employed in the electronics industry. Moreover, the electron localization strategy could revolutionize catalysis and spintronics, enhancing active sites and improving the efficiency of devices that rely on these properties.
Ultimately, the work emanating from the Tongji University research team fundamentally reshapes how one can leverage electron localization to optimize functional materials for addressing real-world challenges like EM pollution. Their use of MSI to manipulate electron dynamics highlights unused potentials within MXenes, offering pathways to greener, more efficient solutions for tackling the environmental concerns that stem from our advanced technological landscape. As global demands for better EM management technologies escalate, the Ni-MXene composites stand poised to become pivotal in developing the next generation of devices, ensuring that innovations in communication and technology can be achieved without compromising our environmental integrity.
Subject of Research: Electron Localization in Metal-Supported MXenes
Article Title: Metal–Support Interaction Induced Electron Localization in Rationally Designed Metal Sites Anchored MXene Enables Boosted Electromagnetic Wave Attenuation
News Publication Date: 23-Jun-2025
Web References: http://dx.doi.org/10.1007/s40820-025-01819-9
References: None available
Image Credits: Xiao Wang, Gaolei Dong, Fei Pan, Cong Lin, Bin Yuan, Yang Yang, Wei Lu.
Keywords
Electromagnetic Waves, MXenes, Nickel Nanoclusters, Absorption Technology, Electron Localization, EMI Shielding, Communication Technology, Nano-Micro Letters.
