Highly stretchable, self-healing, anti-freezing, and moisturizing hydrogel with efficient conductive pathways for self-powered sensing skin electronics

Electronic skin (e-skin), an intelligent material capable of perceiving external stimuli and converting them into electrical signals, has attracted significant attention in the fields of flexible electronics and wearable sensing systems. However, the development of conductive materials that simultaneously possess high electrical conductivity, excellent mechanical robustness, and long-term durability remains a formidable challenge. Herein, we propose a “ one-stone-for-two-birds “ strategy to construct a multifunctional conductive hydrogel through precise regulation of the synergistic interactions between conductive ions and the polymer network architecture. By incorporating bio-based carboxymethyl cellulose (CMC) as a reinforcing component, the hydrogel exhibits greatly enhanced mechanical performance, with a tensile strength of up to 2.13 MPa and an elongation at break of 1950 %. Meanwhile, abundant hydrogen bonding between carboxyl groups and water molecules facilitates the formation of continuous conductive pathways, which significantly promotes ion transport and imparts superior electrical conductivity to the material. Under the combined effects of tunable salt ion environments and dynamic reversible bonding, the hydrogel also demonstrates remarkable water retention, anti-freezing capability, and self-healing properties. Benefiting from this comprehensive set of features, the conductive hydrogel serves as a highly effective flexible electrode for triboelectric nanogenerators (TENGs), enabling efficient energy harvesting. Moreover, it can be integrated into self-powered e-skin platforms with physiological signal sensing capabilities, offering promising prospects for the development of multifunctional and sustainable flexible electronic devices.