Direct Patterning of Conductive Structures on Hydrogels by Laser-Based Graphitization for Supercapacitor Fabrication

Hydrogels have emerged as promising supporting materials for wearable or implantable electronic devices, owing to their high biocompatibility. Among the many techniques for patterning conductive structures on supporting materials, laser-based graphitization allows the simultaneous synthesis and patterning of conductive structures. Here, it has been demonstrated for the first time, the direct patterning of conductive structures on hydrogels by laser-based graphitization, and the application of this method to the fabrication of hydrogel-based supercapacitors. Conductive graphitic carbon is formed on the hydrogel along the trajectory of laser scanning. One-step fabrication of supercapacitors is achieved by laser irradiation of hydrogels containing both lignin and NaCl electrolyte. Notably, the areal capacitance of the fabricated supercapacitor is retained after drying and swelling, indicating its reusability. The method realizes rapid fabrication of hydrogel-based supercapacitors that can be stored in a dry state, providing a facile method for storing and delivering energy-storage devices.