Thermal Transport in Three-Dimensional Foam Architectures of Few-Layer Graphene and Ultrathin Graphite

Abstract

At a very low solid concentration of 0.45 +/- 0.09 vol %, the room-temperature thermal conductivity (K-GP) of freestanding graphene-based foams (GF), comprised of few-layer graphene (FLG) and ultrathin graphite (UG) synthesized through the use of methane chemical vapor deposition on reticulated nickel foams, was increased from 0.26 to 1.7 W m(-1) K-1 after the etchant for the sacrificial nickel support was changed from an aggressive hydrochloric acid solution to a slow ammonium persulfate etchant. In addition, K-GF showed a quadratic dependence on temperature between 11 and 75 K and peaked at about 150 K, where the solid thermal conductivity (K-G) of the FLG and UG constituents reached about 1600 W m(-1) K-1 revealing the benefit of eliminating internal contact thermal resistance in the continuous GF structure.