Free-Standing, Ordered Mesoporous Few-Layer Graphene Framework Films Derived from Nanocrystal Superlattices Self-Assembled at the Solid– or Liquid–Air Interface

Three-dimensional (3D) porous graphene frameworks, which combine the advantages of both porous materials and graphene, have recently attracted enormous attention for electrochemical energy storage. Despite the tremendous progress, it remains a grand challenge to synthesize graphene frameworks with ordered porosity and well-defined macroscopic morphologies. Herein, we report the design and synthesis of centimeter-scale, free-standing thin films of ordered mesoporous graphene frameworks (MGFs) from 2D nanocrystal superlattices self-assembled at the solid– or liquid–air interface. The resultant MGF films possess uniform thicknesses tunable in the range from a few hundred nanometers to several tens of micrometers, highly ordered and interconnected mesoporosity, ultrathin pore walls comprising few-layer graphene, and high surface areas. To demonstrate their potential applications in energy storage, MGF films are used as electrode materials to build supercapacitors, which exhibit high specific capacitances with excellent cycling stabilities in both aqueous and organic electrolytes, with the capacitive performance comparable to or higher than that of most graphene-based materials developed previously.