Laser Scribed Graphene from Oil Palm Lignin for Supercapacitor Applications

This paper reports a facile carbonization method of a biopolymer to synthesize reduced graphene oxide with excellent electrochemical properties for use as a supercapacitor electrode. Oil palm lignin is used as the biopolymer-based graphene precursor, and a carbon dioxide laser is used to carbonize the material via lithography. Using Raman Spectroscopy, the characterization of the resultant graphene (OP-LSG) revealed D, G, and 2D peaks corresponding to multilayer graphene. Scanning Electron Microscopy of OPLSG revealed three-dimensional particle-like fibrous and porous nanostructures with an enhanced surface area. In a three-electrode setup in ferrocyanide electrolyte, cyclic voltammetry showed the electrode coated with OP-LSG achieving a specific capacitance as high as 108.044 mF/cm^2 at a scan rate of 0.01 V/s. The galvanostatic charge-discharge of OP-LSG revealed energy and power density values of 15 μWh/cm^2 and 597 μW/cm^2 at a scan rate of 0.01 V/s. The OP- LSG electrode retained 97.5% of its initial capacitance after 1000 charge-discharge cycles.