Direct preparation and processing of graphene/RuO2 nanocomposite electrodes for high-performance capacitive energy storage. (November 2015)

• Record Type: Journal Article
• Authors: Hwang, Jee Y.; El-Kady, Maher F.; Wang, Yue; Wang, Lisa; Shao, Yuanlong; Marsh, Kristofer; Ko, Jang M.; Kaner, Richard B.
• Is Part Of: Nano energy. Volume 18(2015:Nov.)
• Page Start: 57
• Page End: 70
• Publication Date: 2015-11
• Subjects: Graphene -- Laser -- Ruthenium oxide -- Hybrid capacitor -- Asymmetric supercapacitor -- Micro-supercapacitor; EDLC electrical double layer capacitor -- LSG laser-scribed graphene -- GO graphene oxide -- ICP-AES inductively coupled plasma atomic emission spectroscopy -- SEM scanning electron microscopy -- TEM transmission electron microscopy -- XPS X-ray photoelectron spectroscopy -- TGA thermal gravimetric analysis -- SAED selected area electron diffraction -- CV cyclic voltammetry -- CC galvanostatic charge/discharge -- LED light emitting diode; Nanoscience -- Periodicals; Nanotechnology -- Periodicals; Nanostructured materials -- Periodicals; Power resources -- Technological innovations -- Periodicals; Nanoscience; Nanostructured materials; Nanotechnology; Power resources -- Technological innovations; Periodicals; 621.042
• DOI: 10.1016/j.nanoen.2015.09.009
• Languages: English
• ISSNs: 2211-2855

Abstract

Abstract: Carbon materials are widely used in supercapacitors because of their high surface area, controlled porosity and ease of processing into electrodes. The combination of carbon with metal oxides results in hybrid electrodes with higher specific capacitance than pure carbon electrodes, which has so far limited the energy density of supercapacitors currently available commercially. However, the preparation and processing of carbon/metal oxide electrodes into supercapacitors of different structures and configurations, especially for miniaturized electronics, has been challenging. Here, we demonstrate a simple one-step process for the synthesis and processing of laser-scribed graphene/RuO2 nanocomposites into electrodes that exhibit ultrahigh energy and power densities. Hydrous RuO2 nanoparticles were successfully anchored to graphene surfaces through a redox reaction of the precursors, graphene oxide, and RuCl3 using a consumer grade LightScribe DVD burner with a 788 nm laser. This binder-free, metal current collector-free graphene/RuO2 film was then used directly as a hybrid electrochemical capacitor electrode, demonstrating much-improved cycling stability and rate-capability with a specific capacitance up to 1139 F g − 1 . We employed these hybrid electrodes for building aqueous-based symmetric and asymmetric cells that can deliver energy densities up to 55.3 Wh kg −1, placing them among the best performing hybrid electrochemical capacitors. Furthermore, this technique was used for the direct writing of interdigitated hybrid micro-supercapacitors in a single step for the first time, with great potential for miniaturized electronics. This simple approach provides a general strategy for making a wide range of composite materials for a variety of applications. Graphical abstract: Highlights: This work demonstrates a simple one-step process for the synthesis and processing of laser-scribed graphene/RuO2 nanocomposites into 3D electrodes that exhibit ultrahigh specific capacitances up to 1139 F g −1 . The technique enables the direct laser writing of hybrid micro-supercapacitors in single step for the first time, with energy density comparable to Li-thin battery. Graphene/RuO2 hybrid electrodes can be integrated into an asymmetric electrochemical capacitor operating at a maximum cell voltage of 1.8 V in an aqueous electrolyte. This simple approach opens up the way for a general strategy for making a wide range of composite materials for a variety of applications.