Fabrication of functional laser-induced graphene using gelatin-2,6-diaminoanthraquinone coating for high-performance micro-supercapacitor

In this investigation, we develop a procedure in which gelatin and 2,6-diaminoanthraquinone (ANQ) are combined and then applied as a coating on laser-induced graphene (LIG). The resulting materials are subjected to laser irradiation, which facilitates the introduction of nitrogen doping and the integration of oxygenated functional groups onto the LIG surface. The gelatin polymer played a pivotal role in introducing oxygenated functional groups, while ANQ molecules contributed to both doping with nitrogen and the inclusion of additional oxygenated groups on the LIG surface. The electrode material's performance was enhanced by these functional groups. When evaluated in a three-electrode setup, the ANQ-LIG configuration exhibited a significantly high areal capacitance of 32.4 mF cm−2 at 0.2 mA cm−2, which is five times that of pristine LIG (6.3 mF cm−2) and three times that of gelatin-LIG (9.0 mF cm−2). When integrated into a micro-supercapacitor using a polyvinyl alcohol (PVA)-sulfuric acid (H2SO4) gel electrolyte, ANQ-LIG demonstrated superior areal capacitance (16.0 mF cm−2 at 0.1 mA cm−2) compared to gelatin-LIG (5.3 mF cm−2) at the same current. Additionally, ANQ-LIG displayed favorable capacitance retention (83.8 % after 10,000 cycles) and coulombic efficiency (98.1 % after 10,000 cycles).