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 (CA) 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 CA of 17.96 mF cm−2 is obtained with good cycling stability.