All-solid-state flexible supercapacitor using graphene/g-C3N4 composite capacitor electrodes

Flexible supercapacitors using graphene have been intensively investigated due to their potential applications for wearable and smart devices. In order to avoid stacking between graphene layers, spacers such as carbon fibers and metal oxide particles are often introduced. Such composites enhance effectively the specific surface area of the electrodes and eventually supercapacitor performance. In present work, the graphene/g-C3N4 composite is fabricated and further employed as the supercapacitor electrode. The atomic interaction between C and N of g-C3N4 and O of graphene oxide during the post-reduction in graphene oxide is found to affect device performance. The devices fabricated using the graphene/g-C3N4 composite electrode exhibit a specific area capacitance of 1500 mF cm−2, and 95% of initial capacitance after 5000 cycles and a maximum energy density of 0.075 mWh cm−2. These all-solid-state flexible supercapacitors are thus promising for miniaturized electronics.