Vacuum-Assisted Low-Temperature Synthesis of Reduced Graphene Oxide Thin-Film Electrodes for High-Performance Transparent and Flexible All-Solid-State Supercapacitors

• Published in: ACS applied materials & interfaces 2018-04, Vol.10 (13), p.11008-11017
• Main Authors: Aytug, Tolga, Rager, Matthew S, Higgins, Wesley, Brown, Forrest G, Veith, Gabriel M, Rouleau, Christopher M, Wang, Hui, Hood, Zachary D, Mahurin, Shannon M, Mayes, Richard T, Joshi, Pooran C, Kuruganti, Teja
• Format: Article
• Language: English
• Subjects: flexible electrode; graphene oxide; MATERIALS SCIENCE; optically transparent; supercapacitor; thin film
• ISSN: 1944-8244; 1944-8252
• DOI: 10.1021/acsami.8b01938

Simple and easily integrated design of flexible and transparent electrode materials affixed to polymer-based substrates hold great promise to have a revolutionary impact on the functionality and performance of energy storage devices for many future consumer electronics. Among these applications are touch sensors, roll-up displays, photovoltaic cells, health monitors, wireless sensors, and wearable communication devices. Here, we report an environmentally friendly, simple, and versatile approach to produce optically transparent and mechanically flexible all-solid-state supercapacitor devices. These supercapacitors were constructed on tin-doped indium oxide coated polyethylene terephthalate substrates by intercalation of a polymer-based gel electrolyte between two reduced graphene oxide (rGO) thin-film electrodes. The rGO electrodes were fabricated simply by drop-casting of graphene oxide (GO) films, followed by a novel low-temperature (≤250 °C) vacuum-assisted annealing approach for the in situ reduction of GO to rGO. A trade-off between the optical transparency and electrochemical performance is determined by the concentration of the GO in the initial dispersion, whereby the highest capacitance (∼650 μF cm–2) occurs at a relatively lower optical transmittance (24%). Notably, the all-solid-state supercapacitors demonstrated excellent mechanical flexibility with a capacity retention rate above 90% under various bending angles and cycles. These attributes underscore the potential of the present approach to provide a path toward the realization of thin-film-based supercapacitors as flexible and transparent energy storage devices for a variety of practical applications.