High toughness MXene/ANF-CZIF67/ANF 'magnetic–electric' Janus film for multifunctional low reflection electromagnetic interference shielding

In an era saturated with electronic devices, electromagnetic interference (EMI) poses significant risks to health, data security, and critical systems. Traditional EMI shields often reflect waves, creating harmful secondary pollution. Researchers have now developed an ultra-thin, flexible composite film that not only provides excellent EMI shielding but dramatically reduces this reflective pollution while adding multiple smart functionalities. This breakthrough, published as a peer-reviewed study, paves the way for next-generation wearable and portable electronics. The novel material, named MACA (Magneto-electric Janus structured MXene/ANF-CZIF67/ANF), is exceptionally thin at just 80 micrometers (similar to a sheet of paper) yet remarkably strong and flexible. It achieves an EMI shielding effectiveness of 44.8 dB in the crucial X-band frequency range used by many communication systems. Crucially, its reflection (SE_R) plummets to an ultra-low 4.3-4.5 dB within the 8.2-9.6 GHz band, significantly mitigating secondary electromagnetic pollution – a mr drawback of conventional shields.     

"The exponential growth of electronic devices embeds EMI sources deeply into our living and working spaces," noted a lead researcher involved in the study. "Existing shields often solve one problem by creating another – blocking interference but reflecting waves elsewhere. Our goal was to develop a shield that absorbs the energy, reducing this secondary pollution, without compromising on being thin, lightweight, and crucially, tough enough for real-world use." The MACA film directly addresses the critical need for high-performance EMI shielding that is both environmentally friendlier and mechanically robust for integration into flexible electronics and complex structures.

The film's secret lies in its unique "Janus" (two-faced) structure:

Absorption Layer (CZIF67/ANF): Contains magnetic nanoparticles (CZIF67) derived from metal-organic frameworks, dispersed within a tough network of aramid nanofibers (ANF). This layer efficiently absorbs electromagnetic waves through magnetic and dielectric losses.

Reflection Layer (MXene/ANF): Comprises highly conductive MXene nanosheets (derived from ceramics) interwoven with ANF, providing strong initial reflection.

Biomimetic Bonding: The layers are strongly bonded via hydrogen bonding between the ANF and MXene, creating a unified structure. The ANF forms a 3D network throughout, mimicking natural materials like shells, providing exceptional mechanical strength.

This design creates an "absorption-reflection-reabsorption" pathway, trapping and dissipating electromagnetic energy internally. "The magnetic nanoparticles and the conductive network don't just work side-by-side; they work synergistically," explained a team member. "The Janus structure and the biomimetic ANF network are fundamental to achieving both the low reflection and the high mechanical performance simultaneously."

The MACA film delivers a rare combination: Exceptional Mechanics: Tensile strength of 110 ± 7 MPa and strain up to 21%, making it highly flexible and resistant to folding and rubbing – essential for wearable tech. Low Reflection, High Absorption: Ultra-low reflection (SE_R = 4.3-4.5 dB) combined with effective absorption in target frequencies, minimizing secondary pollution. Multifunctionality: Joule Heating: Rapidly heats to over 200°C at 5V with excellent stability (e.g., 140 ℃ at 3.5V for 1000s), enabling de-icing or personal heating. Infrared Stealth: Effectively masks thermal signatures, useful for security applications. Fire Alarm & Retardancy: Generates an electrical signal upon flame exposure to trigger alarms and exhibits inherent flame resistance. Solar Heating: Efficiently converts sunlight to heat (up to 45 ℃).

Future Applications and Next Steps

"This multifunctional integration is the key takeaway," emphasized a senior author. "We've moved beyond just shielding. We have a single, thin, flexible material that shields EMI cleanly, generates heat, hides from infrared cameras, warns of fire, and is incredibly tough. This opens doors for truly smart, protective materials."

The researchers see immediate potential for MACA films in:

Wearable & Flexible Electronics: Shielding sensitive components in smart clothing, foldable phones, and health monitors without adding bulk or stiffness.

Defense & Aerospace: Providing EMI shielding and infrared stealth for portable equipment, vehicle interiors, and drones.

Sensitive Medical & Research Equipment: Protecting devices from interference with minimal signal reflection.

Smart Infrastructure: Integrating heating and fire-sensing capabilities into building materials or vehicle interiors.

The team is now focused on scaling up the simple vacuum filtration and hot-pressing fabrication process. "Our ultimate goal is to see this technology enable a new generation of safer, more reliable, and smarter electronic devices," the senior author concluded. "The next steps involve optimizing manufacturing for larger areas and exploring integration into specific device architectures."

About the Authors

Liang Benliang is an associate professor and doctoral supervisor in the Department of Materials at the School of Physical Science and Engineering of Beijing Jiaotong University. His research focuses on the modification and regulation of the surface interface of organic and inorganic nanomaterials, as well as the study of their properties. The specific applications include: the preparation and performance research of stealth absorbing materials, electromagnetic shielding materials, thermal conductive and structural strength composite materials. In 2023, he was awarded the Second Prize of the Technology Award of the China Composite Materials Society. He has published over 30 SCI-referenced papers in international important academic journals such as Nano-Micro Letters, Journal of Materials Science & Technology, Nano Research, Composites Science and Technology, and J.Mater. Chem. A. He has 1 hotspot paper, 1 ESI highly cited paper, and 3 authorized invention patents.

About Nano Research

Nano Research is a peer-reviewed, open access, international and interdisciplinary research journal, sponsored by Tsinghua University and the Chinese Chemical Society, published by Tsinghua University Press on the platform SciOpen. It publishes original high-quality research and significant review articles on all aspects of nanoscience and nanotechnology, ranging from basic aspects of the science of nanoscale materials to practical applications of such materials. After 18 years of development, it has become one of the most influential academic journals in the nano field. Nano Research has published more than 1,000 papers every year from 2022, with its cumulative count surpassing 7,000 articles. In 2024 InCites Journal Citation Reports, its 2024 IF is 9.0 (8.7, 5 years), and it continues to be the Q1 area among the four subject classifications. Nano Research Award, established by Nano Research together with TUP and Springer Nature in 2013, and Nano Research Young Innovators (NR45) Awards, established by Nano Research in 2018, have become international academic awards with global influence.