Coordination-Enhanced Interfacial Compatibility of Chitosan-Derived Carbon@CoNi Aerogels for Efficient Electromagnetic Protection and Multifunctionality

Abstract Multicomponent synergy is an effective approach to enhancing the performance of electromagnetic protection materials. However, interfacial incompatibility and structural instability between different components severely limit their practical deployment. To tackle this challenge, this work utilizes the abundant active groups on chitosan molecular chains to coordinate with Co2+ and Ni2+ ions to form a stable suspension, thereby eliminating heterogeneous agglomeration and weak interfacial bonding. Following freeze-drying and high-temperature in-situ reduction, structurally stable CoNi-modified chitosan carbon aerogel (CCA@CoNi) are successfully fabricated. Benefiting from the strengthened interfacial bonding induced by ionic coordination, the optimized composite can sustain a maximum stress of 200 kPa at a compressive strain of 60%. More importantly, the impedance matching of CCA@CoNi composites is effectively optimized by tuning the CoNi alloy loading content. Typically, the CCA@CoNi-2 sample achieves optimal synergism between magnetic and dielectric loss, with a minimum reflection loss (RLmin) of −45.0 dB and an effective absorption bandwidth (EAB) of 5.34 GHz, along with an average electromagnetic shielding effectiveness (EMI SE) of 50.6 dB. Furthermore, the composite integrates excellent thermal insulation, hydrophobicity, corrosion resistance and weather resistance, as well as excellent mechanical stability, exhibiting promising application prospects in harsh environments.