A Petrochemical-Free Route to Superelastic Hierarchical Cellulose Aerogel

Cellulose aerogels are plagued by intermolecular hydrogen bond-induced structural plasticity, otherwise rely on chemicals modification to extend service life. Here, we demonstrate a petrochemical-free strategy to fabricate superelastic cellulose aerogels by designing hierarchical structures at multi scales. Oriented channels consolidate the whole architecture. Porous walls of dehydrated cellulose derived from thermal etching not only exhibit decreased rigidity and stickiness, but also guide the microscopic deformation and mitigate localized large strain, preventing structural collapse. The aerogels show exceptional stability, including temperature-invariant elasticity, fatigue resistance (∼5 % plastic deformation after 10⁵  cycles), high angular recovery speed (1475.4° s^-1 ), outperforming most cellulose-based aerogels. This benign strategy retains the biosafety of biomass and provides an alternative filter material for health-related applications, such as face masks and air purification.