Bio-based aerogel combines electromagnetic shielding, fire resistance, and thermal insulation

Modern aircraft, high-power electronics, electric vehicles, and energy-efficient buildings face a growing combination of risks: electromagnetic interference, fire hazards, heat buildup, and noise pollution. Traditionally, engineers address these challenges separately, layering different materials together. While effective, that strategy increases weight, complexity, and cost, and often relies on petroleum-based components. A new study now proposes a single, lightweight material designed to tackle all four threats at once.

This new study, led by Prof. Ye-Tang Pan and Prof. Pan Chen's group (Beijing Institute of Technology) and Prof. Pingan Song's team (University of Southern Queensland), published in the journal Research on 6^th February 2026, focuses on aerogels, a class of ultralight, highly porous materials known for their excellent thermal insulation.

Conventional aerogels are often brittle, flammable, or limited to just one function. The team set out to rethink the aerogel structure using renewable materials and nanoscale engineering.

“Modern engineering systems rarely encounter only one challenge at a time,” said Prof. Pan “We wanted to design a sustainable aerogel that could simultaneously manage electromagnetic waves, improve fire safety, provide thermal insulation, and absorb sound.”

Central to this is a new material is cellulose, the most abundant natural polymer on Earth and a primary structural component of plant cell walls. Cellulose is renewable, biodegradable, and capable of forming strong three-dimensional networks, making it an attractive foundation for advanced materials. However, untreated cellulose aerogels can burn easily and offer limited electromagnetic functionality.

To overcome these limitations, the researchers created a nickel-based MOFs, directly into the cellulose network. MOFs are porous crystalline materials composed of metal ions linked by organic molecules. Their tunable structures and high surface areas make them useful in applications ranging from gas storage to catalysis.

In this study, the nickel-based MOFs was grown uniformly throughout the cellulose framework, creating an interconnected nanoscale architecture. The composite material then underwent a controlled two-step carbonization process. During heating, portions of the cellulose converted into a conductive carbon framework, while the nickel species transformed into nanoscale nickel phosphide particles embedded within the porous matrix.

“The hierarchical structure that forms during carbonization is essential,” Pan explained. “It creates conductive pathways and abundant interfaces, which are critical for strong microwave absorption.”

Importantly, the final aerogel contains only about five percent filler by weight, helping preserve its ultralight nature while adding multiple protective functions. Electromagnetic testing revealed strong microwave absorption across a broad frequency range. The aerogel achieved a minimum reflection loss exceeding -50 dB, meaning incoming electromagnetic waves were largely dissipated rather than reflected. The researchers also observed a significant reduction in radar cross section, suggesting potential use in electromagnetic interference shielding and stealth-related applications. This performance comes from the synergistic effects of conductive carbon networks and interfacial polarization within the porous structure. The internal architecture allows electromagnetic energy to be effectively attenuated.

Fire safety was another central focus of the study. In combustion tests, the aerogel reduced peak heat release by more than sixty percent compared with untreated cellulose aerogels. The carbonized structure and nickel-derived particles promoted the formation of a stable protective char layer, slowing heat transfer and limiting the release of flammable gases.

“Achieving substantial flame retardancy without traditional halogen-based additives is an important advancement,” Pan noted. “It enhances safety while maintaining environmental responsibility.”

Despite the added functionalities, thermal insulation performance remained strong. The highly porous structure traps air and limits heat conduction, resulting in low thermal conductivity comparable to commercial insulating materials. This allows the material to manage heat while simultaneously providing electromagnetic stealth and fire protection.

Acoustic testing further demonstrated effective sound absorption across a wide frequency range. The interconnected pore network and layered microstructure dissipate acoustic energy through repeated reflections and internal friction, making the material suitable for environments where noise reduction is also required.

Prof. Pan and team acknowledge that the study remains at the laboratory stage. Further work is needed to assess long-term durability, mechanical strength, and performance under real-world environmental conditions.

“We hope this strategy will inspire the development of next-generation sustainable protective materials.” Pan said.

Sources: https://spj.science.org/doi/10.34133/research.1111