Synthesis and characterization of free-standing activated carbon/reduced graphene oxide film electrodes for flexible supercapacitors

Free-standing, binder-free and flexible activated carbon/reduced graphene oxide (AC/rGO) composite films with various ratios were fabricated via a facile vacuum-filtration process. It was proved that two-dimensional rGO sheets were an ideal adhesive support for AC. The optimal ratio (AC : rGO = 2 : 1) was determined and the film electrodes displayed a high area specific capacitance of 486 mF cm−2 with a mass of 2.35 mg cm−2 (specific capacitance of 207 F g−1) at 0.2 mA cm−2. The assembled supercapacitor had the advantages of being flexible, lightweight, cheap and environmentally friendly, and can achieve a superior energy density of 16.2 μW h cm−2 at a power density of 100 μW cm−2 and 85% capacitance retention after 10 000 charging/discharging cycles. Moreover, 90% of the capacitance was retained after 1000 bending cycles and there was almost no performance change under different bending angles. These results well demonstrated a great potential for application of AC/rGO film electrodes in wearable and portable electronics.