Graphene nanostructured materials: self-assembled structures and nano carriers for energy storage and aerospace

In our lab graphene oxide membranes are manipulated into higher order structures. Hollow spherical shells (and other geometries) of graphene oxide are summoned into hierarchical assemblies with control over shell membrane thickness, shell size and composition of binding additives. Intact membranes with shell thickness less than 20 nm have been demonstrated. This allows simultaneous control of the composite’s surface area, surface properties, and transport resistances as related to diffusion and convection. Utilizing graphene oxide and resorcinol-formaldehyde as the basis for these processes allows for well bonded, high strength, structures to be made from these compatible materials. The ultrahigh surface areas attainable through thermal reduction of these constituent materials opens the door to electrophysical applications, such as supercapacitors. The high electrical conductivity, flexibility, and resiliency inherent from these materials is useful for electrochemical applications, such as lithium ion batteries. We have developed a technique to load the interior of these hollow graphene spheres with electrochemically active materials, such as silicon nanoparticles. These silicon nanoparticles/hollow graphene sphere composites holds great promise as anodes for high capacity lithium ion batteries and anodes for batteries based on sulfur cathode chemistry. The graphene membrane spheres are able to confine the electrochemically active silicon to prevent agglomeration which otherwise occurs during thermal reduction and cycling. We have developed a facile method of assembly, through which specific properties can be engineered into these higher order structures. This control is precisely what is required to engineer these graphene oxide and graphene based materials for maximum effectiveness in catalysis, fuel cells, electrophysical and electrochemical processes.Ph.D.Includes bibliographical reference