Available Technology

Graphene Composite Materials for Supercapacitor Electrodes

Developing electrode composite materials that combine graphene with a metal oxide nanocomposite
The method is a two-step, low-cost, scalable solution process of reduced graphene oxide (rGO) and transition metal oxide nanostructures. The deposition of a hybrid metal oxide composite layer of Co304 and Mn02 is done on a current collecting substrate, followed by the electrophoretic deposition of a graphene oxide (GO) top layer. This top GO layer is then chemically reduced, allowing for significant conductivity while creating a porous, high surface area layer atop themetaloxide layer. Reduction typically is accomplished through the use of chemical agents, like hydrazine and sodium borohydride, or by high temperature treatments. The approach uses sodium borohydride as a supplementary reduction method. The variety of methods by which the hybrid metal oxide nanocomposite layer may be deposited onto different current collecting substrates makes this arrangement extremely attractive. Metal oxide nanowire arrays can be deposited using a huge variety of hydrothermal and electrodeposition methods. This range of methods by which the metal oxide component can be deposited onto a conductive substrate also allows for a high degree of flexibility in choosing of the current collecting substrate. The high porosity of the rGO layer is of great importance to allow sufficient diffusion of ions into and out of the metal oxide composite layer. The high specific area of the rGO allows for a high capacitive contribution from the Electrical Double Layer (EDL), while the metal oxide layer provides for a significant increase to the overall energy density of the electrode.
Patent Abstract: 
NASA has developed an electrode composite material capable of both high energy density and high power density relative to conventional batteries. Electrochemical capacitors, or supercapacitors, have gained intense interest as an alternative to traditional energy storage devices in recent years. The applications for the supercapcitors range from plug-in hybrid electric vehicles (PHEVs) to backup power sources. While the power density of supercapacitors surpasses that of batteries, commercially available batteries have a significantly higher specific energy density. This innovation develops electrode composite materials that combine graphene with a metal oxide nanocomposite of manganese oxide and cobalt oxide. It comprises a scalable, integrated materials synthesis and device fabrication process to optimize specific capacitance as well as cycling life time and device reliability. Both energy density and power density are exceptionally high.
Benefits 

Allows for a scalable, low-cost fabrication scheme

applications 

Electric Automobile power sources

Sustainable Energy

Renewable Energy

Energy and Environmental Design

Reps: 
Patent Number: 
8,940,145
Internal Laboratory Ref #: 
TOP2-206
Patent Status: 
Patent Issue Date: 
July 9, 2015
Agency
NASA
Region
Far West
State: 
California
Lab Representatives
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