Fullerenes are molecules made up of 60 carbon atoms in the shape of spheres, cylinders or tubes. Fullerenes are mainly convex polyhedra composed of five-membered and six-membered rings. In terms of molecular orbital energy, fullerenes have large delocalization energy and exhibit metallic luster. In addition, fullerenes have many excellent properties such as superconductivity, strong magnetism, and chemical resistance, and are widely used in catalysts, energy storage, optical materials and other fields. In the field of supercapacitors, it is difficult for a single fullerene material to meet the requirements of high specific capacity, long cycle life, and high power. Therefore, fullerenes are generally combined with conductive polymers and metal oxides to prepare composite electrode materials with excellent performance, thereby improving the energy density and power density of supercapacitors.
Figure 1. Structures of fullerenes
- Electrode material: Supercapacitors are a new type of energy storage device with excellent electrochemical properties. According to the energy storage mechanism, supercapacitors can be divided into two types: (1) Electric double layer energy storage mechanism: mainly rely on the electrostatic accumulation of charges on the electrode surface to store energy; (2) Pseudocapacitive energy storage mechanism: mainly based on fast reversible energy storage mechanism Redox reactions to store energy. Among them, electric double layer capacitors generally use carbon materials as electrode materials. Carbon materials have the advantages of abundant raw materials, simple preparation process, large specific surface area, stable structure, low cost, environmental protection and low toxicity. The pore size distribution, pore shape and structure, specific surface area, electrical conductivity and other factors of carbon materials have a significant influence on the performance of supercapacitors. Fullerenes are a class of three-dimensional multi-carbon materials with a wide pore size distribution and interconnected pores, which can shorten the transmission path and facilitate the transport of ions. In the preparation of high-performance electrode materials, the activation method is used to combine fullerenes with metal oxides to embed metal oxides into a three-dimensional porous conductive network, thereby greatly improving the capacitive performance. In addition, compounding conductive polymers with fullerenes can enhance the stability, cycle life, and capacitance value of electrode materials.
- Ma J, Guo Q, Gao H L. Synthesis of C60/graphene composite as electrode in supercapacitors[J]. Fullerenes Nanotubes and Carbon Nanostructures, 2015, 23, 477482.