Cost effective, metal free reduced graphene oxide sheet for high performance electrochemical capacitor application

A thermally reduced graphene oxide sheet was tested for supercapacitor application. [Display omitted] •Self-assemble graphene oxide sheet 15 × 15 cm was synthesised by the Modified Hummers method.•Thermally reduced GOS has a higher specific capacitance value (469F/g at 1 A/g), which is 8.6-fold higher than the GOS and has excellent cycle stability.•Heat-treated rGO sheet is a strong, cost-effective, and scalable electrochemical capacitor material that could be used in supercapacitors. A simple, cost-effective, and large-scale production of metal-free self-assembled graphene oxide sheets (GOS) with an area of 15 × 15 cm is synthesized using a modified Hummer's method. The reduced graphene oxide sheet (rGOS) was prepared by heat-treating GOS at a range of 300 °C in a hydrogen atmosphere. The XRD results show that GOS has an interlayer distance of 0.79 nm and the rGOS has an interlayer distance of 0.34 nm. The electrochemical analysis of rGOS and GOS was investigated. The porous structure, large-size sheet, and fast transit kinetics of electrochemical analysis and electrons on the interface of electrolyte/electrode contributed to the rGOS showing the high performance of an electrochemical capacitor. The GOS has a specific capacitance value of 54 F/g at 1 A/g, while the reduced GOS has a higher specific capacitance value (469 F/g at 1 A/g), which is 8.6-fold higher than the GOS and has excellent cycle stability. Heat-treated rGOS is regarded as a strong, cost-effective, and scalable electrochemical capacitor material.