Three‑dimensional patterning super‑black silica‑based nanocomposite aerogels

As the demand for advanced thermal management and solar energy technologies intensifies, researchers from Empa – Swiss Federal Laboratories for Materials Science and Technology and Nanjing Tech University have unveiled a breakthrough in multifunctional aerogel design. Led by Dr. Shanyu Zhao, Professor Wim J. Malfait, and Professor Xiaodong Shen, the team has developed 3D-printable super-black silica–carbon composite aerogels that combine ultra-low thermal conductivity, extreme light absorption, and high photothermal conversion efficiency, offering transformative potential for thermal insulation and solar-driven applications.

Why Super-Black Silica-Carbon Aerogels Matter

• Ultra-Low Thermal Conductivity: With a record-low thermal conductivity of 15.8 mW·m^-1·K^-1, these aerogels outperform conventional insulation materials like polyurethane foam and mineral wool, making them ideal for extreme environments.
• Superior Light Absorption: The carbonized composite absorbs 99.56% of light across the 280–2500 nm spectral range, achieving near-perfect optical invisibility and enabling highly efficient solar energy harvesting.
• High Photothermal Efficiency: The aerogel achieves a 94.2% solar-to-vapor conversion efficiency with a water evaporation rate of 2.25 kg·m^-2·h^-1, surpassing most existing photothermal materials.
• Scalable 3D Printing: Enabled by a tailored silica–resorcinol–formaldehyde (RF) ink, the material can be 3D-printed into complex geometries with high shape fidelity, offering customizable designs for real-world deployment.

Innovative Design and Features

• Down–Top Ink Engineering: The ink formulation incorporates hydrophobic silica aerogel particles into an alcohol-based RF sol, optimizing viscosity for direct ink writing (DIW) and enabling high-resolution 3D structures.
• Dual-Network Microstructure: The synergy between the silica framework and carbonized RF matrix suppresses thermal conduction, enhances mechanical strength, and enables broadband light absorption.
• Multifunctionality: Beyond thermal insulation and photothermal conversion, the material exhibits electromagnetic wave absorption with a minimum reflection loss of –48.79 dB and an effective absorption bandwidth of 6.38 GHz, making it suitable for stealth and shielding applications.

Applications and Future Outlook

• Thermal Protection Systems: Ideal for aerospace, defense, and high-temperature industrial environments where lightweight, high-performance insulation is critical.
• Solar-Driven Water Evaporation: The super-black aerogel’s rapid photothermal response and high evaporation efficiency make it a promising candidate for solar desalination and wastewater treatment.
• Electromagnetic Shielding: With tunable dielectric properties and broadband absorption, the composite aerogel can be integrated into radar-absorbing structures and electronic protection systems.
• Challenges and Opportunities: Future work will focus on long-term environmental stability, integration into flexible devices, and scaling up production for commercial deployment.

This pioneering work demonstrates how 3D printing, nanostructured materials, and multiphysics design can converge to create next-generation aerogels with unmatched multifunctionality. Stay tuned for more innovations from the Zhao, Malfait, and Shen teams as they push the boundaries of aerogel technologies for energy, environment, and beyond!