Laser-Induced Reduction of Graphene Oxide by Intensity-Modulated Line Beam for Supercapacitor Applications

Supercapacitors are irreplaceable energy-storage devices for high power output and rapid charge/discharge of electrical energy. In this study, the laser-based fabrication of reduced graphene oxide (rGO) electrodes for supercapacitors is demonstrated with several new features of laser irradiation. A conventional CO2 laser irradiation system is equipped with (1) a nitrogen blower to avoid combustion of the GO paper, (2) a cylindrical lens for producing a wide line beam, and (3) an optical chopper system for generating an intensity-modulated laser beam. Scanning of the intensity-modulated line beam transforms an extended area of GO into chemically reduced and physically porous graphene. The effects of the laser beam modifications and scanning parameters on the electrochemical performance of the rGO electrode are investigated. The rGO electrode exhibits a high specific capacitance (up to ∼130 F/g) at a current density of 1 A/g. This work can serve as a reference for the process optimization of laser-induced GO reduction.