Biomass-derived laser-induced graphene doped with nitrogen and sulfur for enhanced supercapacitor performance

Laser-induced graphene (LIG) offers a straightforward, efficient approach to producing graphene due to its simplicity, patterning capability and cost-effectiveness. Leveraging the sustainability of lignin, a by-product of the pulp and paper industry, we fabricated a supercapacitor with superior performance by laser-scribing graphene from a lignin precursor doped nitrogen (N) and sulfur (S) -containing compounds, on a flexible polyethylene terephthalate (PET) film. By using the LIG as the cathode, a poly(3,4-ethylenedioxythiophene) (PEDOT)-modified LIG as the anode and a flexible polymer electrolyte as a separator, we assembled an effective asymmetric supercapacitor architecture. The device demonstrated a high specific capacitance of 29.94 mF/cm 2 at a current density of 0.15 mA/cm 2 and excellent long-term cycling stability. This fully organic and cost-effective LIG-based supercapacitor device has a potential for future flexible and wearable (bio)electronics, where energy storage demands flexibility and sustainable design for practical applications in portable electronics. • Organic, cost-effective LIG-based supercapacitors were developed from lignin. • In-situ doping of N/S in LIG was achieved by a direct laser-inducing process. • An asymmetric supercapacitor was assembled, with a capacitance of 29.94 mF/cm 2 . • This study could contribute to the circular economy by recycling biomass lignin.