Rapid synthesis of resilient, conductive, and transparent hydrogels with Mo2C-derived polyoxometalates

•A strategy for the rapid synthesis of hydrogels based on POM is proposed.•The strategy can simultaneously improve the mechanical and electrical properties.•The hydrogel has high transparency and can be used in coatings and flexible sensors. Hydrogels have been widely explored as flexible electronics in the fields of electronic skin, implantable devices, human–computer interaction systems, and soft robots. However, the commonly used heat- or light-induced hydrogel polymerization strategies cannot meet the critical demands for rapid preparation. Herein, a redox system assembled by Mo2C-derived polyoxometalates (POM) and ammonium persulfate (APS) for the rapid polymerization (10 s) of high elasticity (1918%), transparency (95%), and conductivity (15 S/m) hydrogels were proposed. The free radicals could rapidly generate from the redox initiator at room temperature without external stimuli of light and heat. By adjusting the amount of POM and APS, the reaction rate can be precisely adjusted from a few hours to seconds to realize the rapid synthesis of high-performance hydrogels. In addition, the POM also could serve as the crosslinking agent to enhance the mechanical properties of the hydrogels. Moreover, the fabricated flexible sensors exhibited highly sensitive electromechanical perception, rapid response, and ultrahigh stability to monitoring different human motions. This strategy paves the way for hydrogel coating, rapid in-situ adhesion, crack repair, and flexible sensors at a low cost.