Ultrathin, transparent, and flexible graphene films for supercapacitor application

This study reports the preparation of ultrathin, transparent graphene films for use in supercapacitor applications. The surface morphology of the films was investigated by scanning electron microscopy and transmission electron microscopy, revealing a very homogeneous surface with intimate contact between graphene sheets. Electrochemical characterization demonstrated nearly ideal electrical double layer capacitive behavior. The capacitance obtained from charge-discharge analysis is 135 F/g for a film of approximately 25 nm which has a transmittance of 70% at 550 nm and a high power density of 7200 W/kg in 2 M KCl electrolyte.