Hollow Bowl-Shaped MXene Material Devours Radar Waves and Harvests Sunlight

A team of materials scientists in China has unveiled a remarkably versatile new material that can do two very different jobs at once: swallow incoming electromagnetic waves with near-record efficiency, and then turn sunlight into usable heat and electricity. The material, described in the journal Advanced Composites and Hybrid Materials, is a hollow, bowl-like heterostructure built from a two-dimensional MXene combined with magnetic FeNi3 nanoparticles, and its performance figures are striking enough to draw attention from anyone working on stealth coatings, 5G and 6G communications, or solar energy conversion.

The research, led by Na Chen and Kang-Jun Wang of Shenyang University of Chemical Technology together with Zhen-Jie Guan and Jian-Tang Jiang of Harbin Institute of Technology, addresses a long-standing frustration in the field of electromagnetic wave absorption. As wireless technology saturates modern life, the electromagnetic environment has grown increasingly crowded and noisy. Radar camouflage, high-frequency communications and dense electronics all generate stray radiation that can interfere with sensitive equipment or reveal the position of military platforms. Absorber materials that convert this radiation into heat are therefore in high demand, but traditional absorbers face an awkward trade-off: designs that absorb strongly across a wide band of frequencies tend to be thick, heavy and single-purpose, while thin, lightweight absorbers usually work only over a narrow range.

The new material breaks through that compromise by borrowing its architecture from nature. The researchers constructed an open, hollow bowl-like structure in which Ti3C2Tx MXene sheets are integrated with FeNi3, an iron-nickel alloy with strong magnetic response. The geometry is not merely decorative. A hollow bowl concentrates and traps incoming waves, forcing them to bounce repeatedly between the curved inner walls, where each reflection dissipates more energy. The open shape also keeps the structure light, since much of its volume is air, and it exposes a large amount of internal surface area where electromagnetic energy can be converted into heat.

The physics behind the absorption is a carefully orchestrated collaboration between three mechanisms. First, where the MXene sheets meet the FeNi3 particles, differences in electronic structure create interfaces across which charges accumulate and migrate. These interfacial charge transports generate polarization losses, converting the oscillating electric fields of incoming microwaves into heat. Second, the material contains oxygen vacancy defects, atomic-scale imperfections that act as additional polarization centers and further enhance dielectric loss. Third, the magnetic FeNi3 component interacts with the magnetic component of electromagnetic waves, adding magnetic loss to the dielectric losses. By tuning the interfacial charge distribution across the heterostructure, the team triggered all three mechanisms to work together rather than in competition.

The measured results are impressive by any standard in the field. The optimized MXene/FeNi3 composite achieved a minimum reflection loss of minus 61.44 decibels. In practical terms, reflection loss quantifies how much of an incoming wave is reflected back rather than absorbed, and each ten-decibel improvement means a tenfold reduction in reflected power. A value beyond minus 60 decibels means that essentially all of the incident microwave energy is being absorbed and dissipated rather than bouncing back toward a radar receiver. Equally important, the material sustains effective absorption, conventionally defined as reflection loss below minus 10 decibels, corresponding to more than 90 percent absorption, across a bandwidth of 6.31 gigahertz at a coating thickness of just 1.91 millimeters. That combination of broad bandwidth and thin profile is exactly what radar camouflage and high-frequency communication shielding demand.

The material also performed strongly in full-scale radar simulations. Its Radar Cross Section, a measure of how detectable an object is to radar, reached a value of minus 45.36 decibels per square meter. Because the decibel scale is logarithmic, this represents an enormous suppression of the radar signature, indicating that a surface coated with the material would appear dramatically smaller to a radar system than the same object without the coating. For military stealth applications and for reducing electromagnetic interference around sensitive civilian electronics alike, this is a meaningful benchmark.

What elevates the work beyond conventional absorber research is the second function: photo-thermo-electric energy conversion. When the material was illuminated under simulated sunlight at the intensity of one sun, its surface reached a steady temperature of 56.7 degrees Celsius, demonstrating efficient photothermal conversion, the ability to turn absorbed light into heat. The material maintained this photothermal performance for more than six hours under the harsher intensity of two-sun illumination, showing that the heating is stable and does not degrade with prolonged exposure, a critical requirement for any practical solar harvesting device.

The harvested thermal energy was then converted into electricity through a thermoelectric effect, in which a temperature difference across a material drives a flow of charge carriers. Under one-sun illumination, the integrated system produced an open-circuit voltage of 225.8 millivolts and a short-circuit current of 38.9 milliamperes. While these outputs are modest compared with conventional photovoltaic panels, the significance lies in the integration: a single material that simultaneously shields against electromagnetic pollution and generates electrical power from sunlight could turn the surfaces of aircraft, buildings or communication equipment from passive shields into active energy harvesters. Waste radiation and ambient sunlight, two byproducts of modern technology, become resources rather than liabilities.

Perhaps the most far-reaching aspect of the study is its generality. The researchers showed that their architecture design strategy extends readily to other magnetic systems, including cobalt, cobalt-iron, cobalt-nickel and iron-cobalt-nickel alloys. This means the hollow bowl-like heterostructure is not a one-off curiosity tied to a specific chemistry but a versatile platform onto which a family of magnetic components can be mounted. Such modularity matters enormously in materials science, because it allows other laboratories to adapt the design to their own requirements, whether they prioritize a particular frequency band, a specific magnetic response or different thermal properties.

The work arrives at a moment when the demands on electromagnetic materials are multiplying. The rollout of 5G networks and the development of 6G technologies are pushing devices toward higher frequencies and greater power densities, intensifying both interference problems and the need for compact shielding. At the same time, the push toward energy self-sufficient electronics and sustainable infrastructure rewards materials that can serve multiple functions in a single lightweight layer. By demonstrating that bioinspired geometry, interfacial engineering and defect chemistry can be combined to dissolve the traditional trade-off between absorption efficiency and multifunctionality, the Shenyang and Harbin team has offered a template for the next generation of integrated electromagnetic materials, ones that do not merely disappear from radar screens but quietly convert the energy they absorb into something useful.

Subject of Research: Multifunctional MXene-based heterostructures for electromagnetic wave absorption and photo-thermo-electric energy conversion

Article Title: Hollow bowl‑like MXene/FeNi3 heterostructures for electromagnetic wave absorption and photo‑thermo‑electric conversion

Article References: Hollow bowl‑like MXene/FeNi3 heterostructures for electromagnetic wave absorption and photo‑thermo‑electric conversion. (n.d.). https://doi.org/10.1007/s42114-026-02125-7

Image Credits: AI Generated

DOI: 10.1007/s42114-026-02125-7

Keywords: MXene, FeNi3, electromagnetic wave absorption, heterostructure, photothermal conversion, thermoelectric, radar cross section, reflection loss, 5G/6G communications, oxygen vacancies, radar camouflage, energy harvesting