Ultrathin Planar Graphene Supercapacitors

Abstract

With the advent of atomically thin and flat layers of conducting materials such as graphene, new designs for thin film energy storage devices with good performance have become possible. Here, we report an ‘in-plane’ fabrication approach for ultrathin supercapacitors based on electrodes comprised of pristine graphene and multi-layer reduced graphene oxide. The ‘in-plane’ design is straightforward to implement and exploits efficiently the surface of each graphene layer for energy storage. The open architecture and the effect of graphene edges enable even the thinnest of devices, made from as grown 1-2 graphene layers, to reach specific capacities up to 80 Fcm-2. While, much higher (394 Fcm-2) specific capacities are observed in case of multi-layered graphene oxide electrodes, owing to the better utilization of the available electrochemical surface area. The performances of devices with pristine as well as thicker graphene based structures are examined using a combination of experiments and model calculations. The demonstrated all solid-state supercapacitors provide a prototype for a broad range of thin-film based energy storage devices.