Exceptional electrical and thermal transport properties in tunable all-graphene papers

Lightweight thermally conductive materials of various electrical features, ranging from insulators such as boron nitride composites to highly conductive graphene-based materials, are increasingly attractive in substituting traditional metal materials for many practical applications. Herein we take a new insight into the electrical and thermal transport properties of the flexible all-graphene papers, where electrically and thermally insulating graphene oxide nanosheets (GO) serve as unique interfaces in the graphene papers stacked by electrically and thermally conductive graphene nanosheets (GN). Anisotropic all-graphene papers with decoupling of thermal and electrical transport properties have been achieved based on controlling the electron and phonon transport paths at the GN-GO interfaces. The fundamental mechanism of the exclusive electrical and thermal transport behaviors in the all-graphene papers has been discussed, indicating more advantageous features in manipulating the transport properties in comparison with other conventional graphene/polymer composites. The implication of the tunable thermal conductivity in the entire semi-conductive range suggests a conceptually novel stage toward fabricating advanced graphene materials of various electrical features for wide thermal management.