(Liaoning Province Key Laboratory of New Functional Materials and Chemical Technology, School of Mechanical Engineering, Shenyang University, Shenyang 110044, China)
Graphene is an electrode material for the new generation of supercapacitors with high specific surface area, excellent chemical stability and mechanical properties. However, the binder is usually added to obtain the graphene electrodes with chemical stability and high density, which will affect the electrochemical performance of the electrods. The free-standing graphene and its composite film is one of the effective ways to solve the problem. The formation methods of graphene free-standing film were introduced, including traditional methods such as suction filtration induced self-assembly, gas-liquid interface self-assembly, coating and layer by layer self-assembly and a novel low-temperature rotary method. The research progress of graphene-based conductive composite films including conductive polymers/graphene, metal oxides/graphene and multi-component composite films was mainly summarized. The future development trends of graphene and its composite free-standing conductive films were proposed, including the development of the new, simple and scaled preparation technology for film electrodes, effective controls of the microstructure of graphene and its composite free-standing films, and applications of various film forming methods in portable electronic devices or flexible batteries.