Spray-Freezing-Engineered Cuttlebone Architectures Enable Multiscale Mechanical Reinforcement in Graphene-Cellulose Aerogels.

Graphene-cellulose aerogels offer lightweight and multifunctional platforms, yet their limited mechanical robustness restricts practical deployment. Herein, we report a bioinspired strategy that integrates novel spray-freezing fabrication with a cuttlebone-mimetic wall-septa architecture to achieve multiscale mechanical reinforcement in graphene-cellulose aerogels. The spray-freezing method allows for scalable production, and the resulting aerogels exhibit an ultralow density of 0.077 g/cm3 while achieving a specific strength of 14.80 kN m/kg and specific modulus of 4.51 kN m/kg at 80% compressive strain, corresponding to 4.95 and 4.96 times those of conventional freeze-dried counterparts. Multiscale simulations reveal that the enhancement arises from two primary mechanisms. At the nanoscale, borax-mediated crosslinking enhances cellulose network integrity, while the bending and load redistribution of graphene nanosheets introduce additional energy dissipation pathways within the lamellar framework. At the mesoscale, horizontal septa in the structure effectively relieve stress concentration during high strain compression. The synergistic coupling of molecular reinforcement and architectural stress redistribution establishes a structure-property paradigm for mechanically resilient cellular nanocomposites. This work provides mechanistic insights into bioinspired multiscale reinforcement and offers a scalable platform for engineering high-performance, lightweight graphene-based aerogels, which is expected to be applied in the thermal and fire prevention fields.