Defect-Engineered Elastic CNC/Chitosan-Based Carbon Aerogel with Wideband Microwave Absorption.

Area of Science:

• Materials Science
• Nanotechnology
• Electromagnetics

Background:

• Growing electromagnetic pollution from 5G/6G necessitates advanced lightweight, broadband, and mechanically robust electromagnetic microwave absorbers (EMWAs).
• Existing carbon aerogels often exhibit structural fragility and insufficient electromagnetic dissipation, limiting their practical applications.

Purpose of the Study:

• To develop a defect-engineering strategy for fabricating elastic boron nitride nanosheet (BNNS)-embedded carbon aerogels with enhanced EM absorption properties.
• To optimize the chitosan (CS)/cellulose nanocrystal (CNC) ratio for synergistic control over microstructure, defect topology, and electromagnetic response.

Main Methods:

• Fabrication of elastic carbon aerogels by embedding BNNS and precisely controlling the CS/CNC ratio.
• Characterization of microstructural, defect topological, and electromagnetic properties.
• Evaluation of electromagnetic absorption performance, including effective absorption bandwidth (EAB) and reflection loss (RL).
• Assessment of mechanical properties, including cyclic compression and elasticity.

Main Results:

• Achieved a wide effective absorption bandwidth (EAB) of 8.3 GHz at 3.6 mm thickness.
• Obtained excellent reflection loss (RL) of -52.79 dB, signifying >99.999% attenuation.
• Demonstrated synergistic effects from CNC-derived defects and BNNS-triggered interfacial polarization for enhanced absorption.
• Engineered optimal graphitization (ID/IG = 1.08) for balanced conductive loss.
• Developed a stable, flexible framework with promising elasticity, retaining 82% height after 1000 compression cycles.

Conclusions:

• The optimized CS/CNC ratio and BNNS integration yield superior broadband EM absorption and mechanical robustness.
• The developed biomass-derived carbon aerogels are suitable for next-generation wearable and conformal EM wave absorbers.
• This defect-engineering approach offers a pathway for advanced materials in electromagnetic pollution mitigation.