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

Researchers in China have developed a novel MXene-based material that effectively absorbs electromagnetic waves and converts sunlight into heat and electricity. The material, detailed in the journal Advanced Composites and Hybrid Materials, features a hollow, bowl-like heterostructure composed of a two-dimensional MXene integrated with magnetic FeNi3 nanoparticles. This design is particularly relevant for applications in stealth coatings, 5G and 6G communications, and solar energy conversion.

The study, led by Na Chen and Kang-Jun Wang from Shenyang University of Chemical Technology, along with Zhen-Jie Guan and Jian-Tang Jiang from Harbin Institute of Technology, tackles the challenge of electromagnetic wave absorption in increasingly crowded electromagnetic environments. Traditional absorbers often face a trade-off between thickness and absorption bandwidth. The new MXene/FeNi3 composite overcomes this by using a hollow structure that traps and dissipates incoming waves efficiently, while remaining lightweight.

The absorption mechanism involves three key processes: interfacial charge transport between MXene sheets and FeNi3 particles, oxygen vacancy defects enhancing dielectric loss, and magnetic loss from the FeNi3 component. The composite achieved a minimum reflection loss of minus 61.44 decibels, indicating near-total absorption of incident microwave energy. It also maintains effective absorption across a 6.31 gigahertz bandwidth at a thickness of just 1.91 millimeters, meeting the demands of radar camouflage and high-frequency communication shielding.

In radar simulations, the material's Radar Cross Section was reduced to minus 45.36 decibels per square meter, significantly lowering its detectability. This makes it valuable for both military and civilian applications where electromagnetic interference is a concern. Additionally, the material demonstrates efficient photothermal conversion, reaching 56.7 degrees Celsius under one-sun illumination and maintaining performance under two-sun conditions.

The thermoelectric effect allows the material to convert thermal energy into electricity, producing an open-circuit voltage of 225.8 millivolts and a short-circuit current of 38.9 milliamperes under one-sun illumination. While modest, these outputs highlight the potential for integrated systems that shield against electromagnetic pollution while generating power from sunlight.

The research suggests that the hollow bowl-like heterostructure can be adapted to other magnetic systems, offering a versatile platform for various applications. As the demand for multifunctional electromagnetic materials grows with the advancement of 5G and 6G technologies, this study provides a promising template for future developments.