Structural regulation and coupled electrical-magnetic properties of biomass-derived Fe-incorporated carbon aerogels

To develop biomass‑derived magnetic conductive carbon aerogels toward energy storage and electromagnetic shielding applications, magnetic conductive carbon aerogels were rationally fabricated using chitosan (CS) and sodium carboxymethyl cellulose (CMC) as raw biomass precursors via Fe 3+ coordination cross-linking, directional freeze-drying and high-temperature carbonization strategies. The effects of precursor ratio on the microscopic morphology and electrical conductivity of as-prepared aerogels were systematically explored. The results indicated that the optimized CS/CMC-50%-C aerogel possessed a large specific surface area of 458.9 m 2 ·g −1 , well-developed hierarchical porous architecture and superior graphitization degree. During high-temperature pyrolysis, in situ generated Fe 3 O 4 nanocrystals together with formed Fe–C bonds successfully endowed the aerogel with favorable magnetic behavior and simultaneously reinforced the interconnection of internal conductive networks. Benefiting from the above structural and compositional merits, the resultant aerogel achieved low resistivity of 0.454 Ω·cm and maintained stable electrical conductivity and integral structural integrity after ten consecutive charge–discharge cycles. This work provided a promising route to prepare lightweight magnetic conductive biomass aerogels. Graphical abstract High-porosity precursor aerogels were prepared from Fe 3+ cross-linked biomass via directional freezing, and the subsequent carbonization yielded magnetic carbon aerogels with 3D porous structure and excellent electrical conductivity stability.