Ionic liquid directed assembly of wrinkled and porous composite electrode for high-power flexible supercapacitors

© The Royal Society of Chemistry 2014. To meet the pressing demands for portable and flexible electronic devices in contemporary society, it is strongly required to develop next-generation flexible and sustainable supercapacitors with high capacitance, high energy and power densities. Here, by using carbon nanotube/ionic liquid as a surfactant-like agent, a flexible all-solid-state supercapacitor device with three-dimensional (3D) reduced graphene oxide/polyaniline composite electrode membranes was fabricated. The fabrication process relies on the surfactant like structure of ILs which contains both ionic and aromatic groups. As the aromatic groups have a tendency to make strong ?-? interactions with aromatic carbons, the self-assembly process of ILs also brings the organization of the attached carbon composite materials into a wrinkled and porous nanostructure. The obtained pliable supercapacitor can deliver a high specific capacitance of 154.12 F g^-1, a high power density of 17.21 kW kg^-1 and a stable cycling durability with 86.3% capacitance retention after 1000 charge-discharge cycles. The high performance of the as-prepared electrode film was ascribed to its unique nanostructure composed of micro and mesopores. The ionic liquid directed assembly method developed here also provided a new idea for structural controlled preparation of graphitic carbon nanomaterials.