Synergistic cell-wall architecture tuning and skeleton reinforcement for wood sponges with superelasticity and exceptional fatigue resistance.

Elastic wood sponges are sustainable, low-cost, and multifunctional materials that have gained extensive attention and rapid development. However, their dense cell walls and fragile cellulose skeleton severely constrain the compressive recoverability and fatigue resistance. This constraint hinders their use as an elastic functional material toward high-performance, advanced applications. Herein, a synergistic strategy that combines multilevel cell-wall engineering with skeletal reinforcement is developed to fabricate superelastic and fatigue-resistant wood sponges. Specifically, by integrating the selective removal of non-skeletal components of the cell walls with a multi-hierarchical arched lamellar microstructural design and a robust hydrogen-covalent dual crosslinking network, wood sponges with expanded spacing and arched lamellar structure are obtained. Benefiting from this structure, the sponges achieve unprecedented elasticity (100% and 94.10% single-cycle height recovery at 90% and 95% compression strain, respectively) and superior fatigue resistance (96.99% height retention rate at 50% strain under 10 000 cycles). After conductivity modification, they exhibited multifunctional pressure-sensing capabilities with a broad detection range (1.57 MPa), high sensitivity (9.73 kPa-1), and exceptional signal stability (12 000 cycles). These superior metrics guarantee broad applications in machine learning-assisted motion/gesture recognition and human-machine interaction. This work offers a novel perspective for designing multifunctional, superelastic, and fatigue-resistant wood sponges through structural construction.