Simple fabrication of Co₃O₄ nanoparticles on N-doped laser-induced graphene for high-performance supercapacitors

This study demonstrates a simple strategy to fabricate Co₃O₄ on N-doped laser-induced graphene (Co₃O₄-NLIG) based on duplicate laser pyrolysis, enabling the in situ generation of Co₃O₄ nanoparticles and heteroatom doping in laser-induced graphene (LIG). Morphological analyses reveal the uniform distribution of Co₃O₄ nanoparticles on the surface of the LIG structure. The modification of NLIG with Co₃O₄ nanoparticles results in impressive electrochemical performance due to the contributions from electric double-layer capacitance and pseudocapacitance. The optimal Co₃O₄-NLIG is produced at 20 wt% cobalt precursor loading (Co₃O₄-NLIG-20). In a three-electrode setup, this electrode exhibits a specific areal capacitance (C _A) of 216.3 mF cm^-2 at a current density of 0.5 mA cm^-2 in a 1 M KOH electrolyte. When the optimal electrodes are assembled into a solid-state supercapacitor (Co₃O₄-NLIG-SC) using a poly(vinyl alcohol) phosphoric acid (PVA-H₃PO₄) gel electrolyte, a C _A of 17.96 mF cm^-2 is obtained with good cycling stability.