Laser-assisted transformation of a phenol-based resin to high quality graphene-like powder for supercapacitor applications

Abstract

Synthesis of high-quality graphene-like structures by means of an eco-friendly, cost effective, one-step and scalable method is highly sought after. Some of these traits have been successfully addressed in recent studies employing laser irradiation in the synthesis process, however, reports on laser-assisted high-quality graphene growth overwhelmingly rely on the rather costly polyimide precursor. In this study, we report laser-mediated synthesis of high-quality graphene powder, originating from a phenol-based resin. Raman spectroscopy and X-ray diffraction findings suggest turbostratic, i.e., rotationally faulted, stacking of graphene layers, while the porous structure of the produced material is revealed by scanning electron microscopy. X-ray photoelectron spectroscopy was employed to probe the chemical composition of the materials before and after irradiation, and revealed the high C/O ratio value (22.6) in the irradiated powder. Moreover, the potential of these graphene-like structures in energy storage applications are investigated in aqueous supercapacitors, using both three- and two- electrode configurations. The excellent conductivity is validated from both sheet resistance measurements 40Ohmsq-1 and the very low ohmic losses during galvanostatic charge discharge measurements. The two-electrode device showed a capacitance of 17.2 Fg−1 at 10 mVs−1, a fairly good rate performance 67% up to 200 mVs−1 and excellent cycling stability (87.2% after 20,000 cycles).