Three-Dimensional Nanographene as a Low-Cost Tunable Bulk Material

J. Biener, A. Wittstock, S. Dasgupta, L.-H. Shao, D. Wang, M.A. Worsley, J.R.I. Lee, M.M. Biener, C. Orme, S.O. Kucheyev, B.C. Wood, T.M. Willey, A.V. Hamza, J. Weissmüller, H. Hahn, T.F. Baumann
Lawrence Livermore Nat Laboratory, US

Keywords: graphene, nanostructured material, super capacitor, actuator

Summary:

Nanocarbon materials such as graphene are largely consisting of surface atoms. As a conse-quence, their properties can be addressed through various interfacial phenomena which opens the door to new applications in the field of actuation and sensorics. Taking full advantage of this unique opportunity requires the availability of macroscopic, monolithic materials. Here, we show that three-dimensional bulk nanographene (3D-NG) can be fabricated as centimeter-sized monoliths through thermal activation of polymer-derived carbon foams. The material is electrically conductive and mechanically robust while possessing a gravimetric surface area exceeding the theoretical value for a free-standing graphene sheet. The unique structural properties of 3D-NG provide the opportunity to dynamically tune its bulk properties by interfacial charging. For example, we demonstrate fully reversible electrical conductivity changes of several hundred percent and macroscopic strain amplitudes of more than two percent by injection/depletion of only a percent of an electronic charge per carbon atom. We will compare to experimental and theoretical results on 2 dimensional multi layered graphene samples as a bench mark. Our findings open the door to new 3D applications of graphene including an all-carbon bulk transistor.