Nickel-oxide embedded laser-induced graphene for high-performance supercapacitors†

Abstract

This study explores the fabrication of nickel-oxide-embedded laser-induced graphene and its application in high-performance supercapacitors. Supercapacitors are critical for various applications due to their high power density and long cycle life. Nevertheless, they suffer from lower energy density compared to batteries. By embedding redox-active nickel oxide (NiO) nanoparticles into graphene electrodes, we enhance the energy density of these supercapacitors while maintaining high power. The NiO nanoparticles were synthesized at the nanoscale and embedded into graphene oxide (GO) using a one-step laser processing technique, resulting in a composite material with improved electrochemical properties. High specific capacitance for a discharge current density of 0.25 A g⁻¹ is 1420 F g⁻¹ in 6 M KOH. Moreover, by tracking the crystallographic X-ray diffraction (XRD) pattern of the composite electrodes upon electrochemical cycling, we identified the phase transition from NiO to Ni(OH)₂. Our results verify the advantages of laser processing to incorporating highly-dispersed NiO nanoparticles into graphene films, which significantly enhances the electrochemical performance of supercapacitors, offering a promising approach for developing high-energy and high-power energy storage devices.