Green and Low‐Cost Alkali‐Polyphenol Synergetic Self‐Catalysis System Access to Fast Gelation of Self‐Healable and Self‐Adhesive Conductive Hydrogels for Self‐Powered Triboelectric Nanogenerators

Abstract Biomass‐based hydrogels have attracted great attention in flexible and sustainable self‐powered power sources but struggled to fabricate in a green, high‐efficiency, and low‐cost manner. Herein, a novel and facile alkali‐polyphenol synergetic self‐catalysis system is originally employed for the fast gelation of self‐healable and self‐adhesive lignin‐based conductive hydrogels, which can be regarded as hydrogel electrodes of flexible triboelectric nanogenerators (TENGs). This synergy self‐catalytic system comprises aqueous alkali and polyphenol‐containing lignin, in which alkali‐activated ammonium persulfate (APS) significantly accelerates the generation of radicals and initiates the polymerization of monomers, while polyphenol acts as a stabilizer to avoid bursting polymerization from inherent radical scavenging ability. Furthermore, multiple hydrogen bonds between lignin biopolymers and polyacrylamide (PAM) chains impart lignin‐based hydrogels with exceptional adhesiveness and self‐healing properties. Intriguingly, the alkaline conditions not only contribute to the solubility of lignin but also impart superior ionic conductivity of lignin‐based hydrogel that is applicable to flexible TENG in self‐powered energy‐saving stair light strips, which holds great promise for industrial applications of soft electronics.