Carbon is widely present in nature. In addition to the most well-known graphite and diamond, fullerenes discovered in 1985 and carbon nanotubes discovered in 1991 expanded the family of carbon materials. It also enables people to have a deeper understanding of the diversity of carbon elements. At the same time, nanotechnology triggered by fullerenes and carbon nanotubes is of great significance to the development of human society in the future. As the newest member of carbon materials, graphene is a two-dimensional carbon atom crystal with sp2 hybrid orbitals. It was discovered in 2004 by Geim of the University of Manchester, UK, and can exist stably. It is currently the thinnest material in the world. A material with a thickness of one atom. Graphene not only has excellent electrical properties (the electron mobility can reach 200,000cm2V-1s-1 at room temperature), it is light in weight, has good thermal conductivity (5000Wm-1K-1), and has a large specific surface area (2630m2g-1). Modulus (1100GPa) and breaking strength (125GPa) are also comparable to carbon nanotubes, and they also have some unique properties, such as quantum Hall effect, quantum tunneling effect, etc. Due to the above unique nanostructure and excellent performance, graphene can be used in many advanced materials and devices, such as thin film materials, energy storage materials, liquid crystal materials, mechanical resonators, etc. Graphene is a single-layer graphite with easily available raw materials, so it is cheap and not as expensive as carbon nanotubes. Therefore, graphene is expected to replace carbon nanotubes as a high-quality filler for polymer-based carbon nanocomposites. Among the many properties of graphene, the specific surface area is high and the conductivity is good. The most important thing is that the capacitance of graphene itself is 21μF/cm2, reaching the upper limit of all carbon-based electric double layer capacitors, which is higher than other carbon materials. , Is an ideal material for manufacturing supercapacitors.

　　Supercapacitors, also called electrochemical capacitors, are a new type of energy storage device with energy density and power density between traditional capacitors and batteries. Supercapacitors have the advantages of batteries and traditional capacitors, such as energy density. High, high power density, fast charge and discharge, long cycle life, instantaneous high current discharge and no pollution to the environment. It is a new type of energy storage and energy saving equipment developed in the past ten years.

　　Since graphene is an ideal filling material for supercapacitors, it has attracted much attention to compounding it with other materials to prepare supercapacitor materials.

　　There are two main types of composite materials. The first is the composite of graphene and polymer conductive materials. Among them, the most studied composite material is graphene and polyaniline. The second is the composite of graphene and metal oxide, of which the most researched is the composite of graphene and manganese dioxide. This article mainly summarizes the research of these two kinds of composite materials.

　　Graphene and polyaniline composite materials are used in supercapacitor materials. In addition to the special properties of graphene mentioned above, polyaniline has the advantages of high conductivity, easy synthesis, and low monomer cost. Zhao et al. prepared polyaniline/graphene composites by in-situ polymerization under acidic conditions, and found that polyaniline was uniformly adsorbed on the surface of graphene, or evenly dispersed between graphene sheets, at a current density of 0.1A/ At g, the specific capacitance is as high as 480F/g, and it has good cyclability.

　　Li et al. conducted in-situ anodic electropolymerization on graphene sheets to generate polyaniline, and the resulting composite material had a tensile strength of 12.6MPa and a high and stable electrochemical capacitance (weight specific volume of 233F/g, volume specific volume of 135F/ cm3), more than many other currently available carbon-based flexible electrodes, so it has great prospects in flexible supercapacitors.

　　Shi et al. first prepared a stable mixture of chemically modified graphene and polyaniline fibers, and then vacuum filtered to obtain graphene/polyaniline fiber film composites, in which the polyaniline fibers were evenly dispersed between the graphene interlayers The composite material has stable mechanical properties and high flexibility, and can be bent at a large angle to obtain the desired shape. When the content of modified graphene is 44%, the capacitance is the largest, 210F/g.

　　Yan et al. reported that a composite paper of polyaniline and graphene was obtained through a simple and rapid solution mixing and in-situ polymerization method. This composite material has good electrical properties. It is worth mentioning that the composite paper is in biological The field has potential application value. Wei et al. compounded functionalized graphene and polyaniline nanoparticles to obtain a capacitance of 1046F/g, which is almost twice that of pure polyaniline materials.

　　The second is the composite of graphene and metal oxide, and the most researched is the composite of graphene and manganese dioxide. Wei et al. mixed potassium permanganate with graphene and used microwave radiation to reduce potassium permanganate to manganese dioxide. The reduced manganese dioxide was deposited on the surface of graphene. This composite material was used as the anode and activated carbon was used as the cathode. The capacitance is 114F/g,

　　The number of cycles can reach 1000 times to obtain a super capacitor. Yang et al. obtained a composite material of multilayer polydiallyldimethylammonium chloride modified blackstone and manganese dioxide through a self-assembly method, which has a higher capacitance and a higher number of cycles.

　　In summary, with the continuous progress of society, the continuous consumption of resources, and the continuous development of the economy, graphene composite materials will surely play an extremely important role in the future electronic field.