Towards High Performance Flexible Planar Supercapacitors: In-situ Laser Scribing Doping and Reduction of Graphene Oxide Films

Abstract A novel, scalable, single-step and low-synthesis temperature fabrication approach is proposed for real-time doping, reduction, and patterning of graphene oxide-based films supported on flexible polyethylene terephthalate (PET) substrate using a CO2 Laser system. Laser reduced graphene oxide (LrGO), nitrogen-doped laser reduced graphene oxide (N-LrGO), and sulfur-nitrogen co-doped laser reduced graphene oxide (SN-LrGO) planar supercapacitors (PSCs) are readily fabricated with the proposed approach. Structural and elemental characterizations prove the successful integration of nitrogen and sulfur atoms into the graphene framework with high contents up to 3.71 at% N and 1.82 at% S, and at a low density of structural defects. An areal capacitance as high as 13.8 mF cm-2 at 10 mV s-1 and a maximum power density of 151.7 mW cm-3 at an energy density of 0.152 mWh cm-3 is achieved by SN-LrGO PSC composed of 10 interdigitated fingers with an excellent retention rate after 2000 charging/discharging cycles at 0.125 mA cm-2. Furthermore, higher operating voltage window and current ratings are easily achieved via series and parallel combinations of SN-LrGO PSCs directly on the same substrate. This manifests the versatility of the proposed approach for producing flexible and high-performance graphene-based electrochemical storage devices.