Self-assembled reduced graphene oxide films with different thicknesses as high performance supercapacitor electrodes

Graphene-based materials have attracted considerable attention as the electrochemical energy storage and conversion material due to their high electronic conductivity and large ion-accessible surface area. Herein, a series of self-assembled reduced graphene oxide (rGO) films are facilely prepared via a scalable vacuum filtration method, whose thickness is regulated by changing the concentration of the filtering rGO solution. The effect of the mass loading (thickness) of rGO film electrodes on its electrochemical performance is investigated. These rGO film electrodes with mass loading of 6.7 mg cm⁻² exhibit a high specific capacitance of 173.4 F g ⁻¹ (1.16 F cm⁻²) at 1 A g ⁻¹ and show high utilization of the active material due to their large specific surface area and uniform pore distribution. Moreover, a quasi-solid supercapacitor fabricated with the as-prepared rGO film electrode shows a high area capacitance of 1.03 F cm⁻² and large specific energy of 0.073 mWh cm⁻² at the specific power of 3.3 mW cm⁻², as well as excellent cycling stability of 85.6% retention after 10,000 cycles. Such remarkable performance suggests that this rGO film is promising electrode material for supercapacitor application.