Multifunctional asymmetric bilayer aerogels for highly efficient electromagnetic interference shielding with ultrahigh electromagnetic wave absorption

As 5G base-stations mushroom and drones patrol from the stratosphere, electromagnetic pollution, infrared surveillance, and oil-spill disasters increasingly arrive in the same breath. In a sweeping review published in Nano-Micro Letters, a Beijing University of Chemical Technology team led by Professors Hao-Bin Zhang and Zhong-Zhen Yu reveals an asymmetric MXene-graphene bilayer aerogel that neutralizes all four threats simultaneously. Printed in minutes from a single emulsion ink, the 12 mg cm^-3 foam weighs less than a postage stamp yet delivers >100 dB EMI shielding, 115 °C solar-thermal heating, dynamic IR camouflage, 0.032 W m^-1 K^-1 thermal insulation, and 10× its own weight in oil absorption—all without external power beyond sunlight or a 1–3.5 V pulse.

Inside the Bilayer Design: From Reflection to Re-Absorption

Traditional metal foils reflect 90 % of incident waves, creating secondary pollution. The new design flips the paradigm:

• Top MG layer (MXene + GO) fine-tunes impedance like a gateway, letting waves enter instead of bouncing them away.
• Bottom MXene layer acts as an internal mirror, reflecting any residual energy back through 46 µm spherical closed pores where ohmic loss, dipole polarization, and multiple scattering finish the job.
• Result: an absorption coefficient of 0.95 across 8.2–40 GHz while reflection stays below 0.05—an order-of-magnitude improvement over copper-backed foams.

Finite-element simulations show electric fields trapped inside the spherical pores rather than the aerogel surface, confirming absorption dominance.

Five Missions, One Material

1. Electromagnetic Shielding
   3D-printed lattice covers attenuate Bluetooth signals to zero, preserving the >100 dB shielding of copper foil while adding almost no mass.
2. Solar-Thermal Heating & De-icing
   Under 150 mW cm^-2 sunlight, the black MXene surface hits 115 °C in 80 s, melting 0.2 mL of ice in one minute—ideal for aircraft wings or soldier helmets.
3. Dynamic Infrared Camouflage
   A 1.21 V pulse drives the surface from ambient to 45 °C, matching background heat signatures in real time. Cycle tests over 50 on/off events show <0.5 °C drift.
4. Thermal Insulation & IR Stealth
   A 1 cm sheet keeps an 80 °C source below 39 °C on the exposed side, cloaking engines from thermal cameras while remaining hand-safe.
5. Oil-Water Cleanup
   The 131° water-contact-angle surface absorbs cyclohexane in 20 s and viscous crude in 60 s under solar heat, then releases the oil by gentle squeezing—fully reusable after ultrasonic cleaning.

Ink to Infinity—Scalable, Sculptable, Sustainable

The magic starts with a Pickering emulsion ink: MXene and graphene oxide sheets self-assemble with octadecyl amine at the oil-water interface, forming nano-surfactants that jam droplets into a printable gel. Rheology is tuned by stirring speed and phase ratio, enabling direct-ink-writing into lattices, petals, or meter-scale sheets on standard 3-D printers. After freeze-drying, the closed-cell spherical pores survive folding, flexing, and even 3 h of ultrasonic agitation in water.

The entire process uses commodity MXene and GO, no toxic solvents, and is compatible with roll-to-roll molding—clearing the path for kilogram-scale production.

Roadmap to the All-Weather, All-Threat Garment

Next steps embed the aerogel into helmet liners for soldiers, drone skins for logistics, or emergency blankets for disaster zones. Early prototypes already cloak a soldier’s head from IR drones while powering a pocket heater from sunlight alone. One material, five functions, zero compromise—the future of multifunctional protection is ready to print on demand.