Facile Synthesis of Nickel Ferrite Decorated Carbon Nanotube/Cellulose Aerogel for Efficient Electromagnetic Wave Absorption

The continuous advancement of electronic devices, driven by trends toward miniaturization, reduced weight, higher integration, and multifunctionality, imposes stringent requirements on the performance of electromagnetic wave (EMW) absorbing materials. Traditional EMW absorbers, such as metals, face significant drawbacks, including high density and rigidity, which limit their broader application in EMW absorption. To overcome these issues, cellulose is employed as the matrix, incorporating nickel ferrite (NiFe₂O₄) nanocrystals and carbon nanotubes (CNTs) as functional fillers. The ferrite/CNT/cellulose aerogels (NCCAs) are fabricated through ionic crosslinking and room-temperature drying techniques. The results show that the porous structure of NCCA enhances multiple scattering and energy dissipation pathways for EMWs, while CNTs provide excellent electrical dissipation. The content of NiFe₂O₄ nanocrystals strongly influences the aerogel's saturation magnetization and the electromagnetic parameters of the NCCAs, primarily owing to their superior dielectric and magnetic loss properties. Notably, when the content of NiFe₂O₄ nanocrystals is 4% of the cellulose mass, the NCCA achieves the lowest reflection loss of -66.53 dB at 16.11 GHz, and lower than most reported ferrite-based EMW absorbers. This work provides valuable insights and guidance for the design of novel aerogel-based EMW absorbers with lightweight properties, strong absorption intensities, and broad absorption frequency bands.