Water vapor-mediated cellulose skeleton enhances liquid-free ion-conductive elastomers for flexible electronics

Liquid-free ion-conductive elastomers represent an attractive platform for flexible electronics by circumventing the leakage and instability inherent to conventional hydrogels and ionogels. Despite the ability of polysaccharide fillers to address the low overall performance in single-network, liquid-free ion-conductive elastomers, balancing their conflicting electrical and mechanical properties is hindered by poor filler dispersion. Here, we introduce a green water vapor-mediated regeneration strategy to construct a cellulose filler skeleton. By effectively lowering the cellulose regeneration rate to resolve structural inconsistency and surface roughness, this strategy produces a more homogeneous cellulose skeleton, thus allowing its uniform dispersion within the PDES matrix. The uniform 3D porous cellulose framework, rich in hydroxyl groups, synergistically forms a homogeneous network with polyacrylic acid. This enables effective energy dissipation by providing additional reversible hydrogen bonds and also offers stable pathways for free ion migration. The as-fabricated elastomer composite exhibits exceptional mechanical robustness with a tensile strength of 3.1 MPa, Young's modulus of 1.63 MPa and toughness of 13.0 MJ/m 3 , together with tunable ionic conductivity (1.1–3.2 × 10 −2 S/m), enhanced environmental stability, and intrinsic self-healing capability. PDES-VC-2% withstands 10,000 cycles at 200% strain without fracture, and maintains stable signal output for approximately 680 cycles. Consequently, strain sensors from this elastomer are employed for human motion monitoring, information encryption, and handwriting recognition. A battery fabricated with it as the solid-state electrolyte achieves a 0.731 V open-circuit voltage and stable 14-day operation, making it suitable for both charging capacitors and driving self-powered sensing, with both repeatability and sustainability. This work provides a sustainable strategy for constructing internal networks in ionic conductors using polysaccharides, opening new opportunities for multifunctional and environment-friendly soft iontronics. • Novel water vapor-mediated strategy builds a homogeneous cellulose skeleton. • The 3D network lays the structural foundation for stress transfer and ion transport. • Elastomers exhibit enhanced mechanical property, conductivity, and stability. • Elastomers sensors are applied for human motion detection and information encryption. • Elastomers as solid-state electrolyte in battery give 0.731 V open-circuit voltage.