Graphene/Naphthalene Sulfonate Composite Films with High Electrical and Thermal Conductivities for Energy Storage and Thermal Management in Nanoscale Electronic Devices

Electrical and thermal conductivities of graphene-based composites are inferior to the expectation mainly because of the difficulty in optimization of the defects and spatial distribution of graphene in the matrix under high loading. In this study, high electrical and thermal conductivities of free-standing and flexible graphene/naphthalene sulfonate (GN) composite films are achieved by controlling the assembly of few-defect flat graphene sheets. The assembled GN composite film exhibits excellent electrical conductivity reaching at 1.25 × 10⁵ S m^–1, leading to a high electromagnetic shielding performance that is up to 37 dB when the thickness of the film is only 25 μm, which is competitive with previously reported millimeter-thickness graphene composite films. Moreover, the GN composite film also shows excellent in-plane thermal conductivity (300 W m^–1 K^–1). Such superior properties of the film are mainly because few-defect graphene can form highly orientated structures in the composite under high loading. We foresee that the obtained composite films have great potential applications in the fields of energy storage and thermal management of the nanoscale electronic devices.