New-Type Carbon Nanomaterials:Design, Preparation And Study Of The Electrochemical Performance

In the21st century, energy shortages and environmental pollution have influenced the economy and people□s life. Therefore, the key to solve this problem is development of new energy storage device which can replace the internal combustion engine. These new energy storage devices include fuel cell, Li ion battery, and supercapacitors. Meanwhile, how storage the energy has become the research important topic.Supercapacitors, also known as electrochemical capacitors (ECs), are a class of electrochemical energy storage devices that complement batteries. They have received considerable attention worldwide because of their potentially high-impact characteristics including high power density (10KW kg-1), long cycle life (>105), high reliability, and low maintenance. Such outstanding properties make them auspicious electrochemical energy storage devices in a wide range of applications, such as various portable electronic device, hybrid motor vehicle, large industrial equipments and military devices. Since their performance mainly depends on the electrode materials, it has been extensively pursued to get high quality materials with low cost and easy ways.Graphene is a special single atomic layer structure which decides its extraordinary properties including high electrical conductivity, unusual mechanical strength and ultralarge specific surface area. Therefore, it has a wide range of applications in the field of new energy and is preferable to replace other carbon matrices. However, the high cost limits its widespread use. In addition, it also exits structural defects and provides the energy density far lower than that of faradaic materials. Therefore, it is important to focus on the synthesis of graphene-based composites and its application as electrode materials for energy storage devices.In this paper, we use the materials from the perspective of economy and cheaply, and get a based-graphene nanocomposite. The main research content is as follows:Vanadium pentoxide (V9O5) has attracted much attention for energy storage application due to its high Faradaic activity and stable crystal structures, which make it promising electrode materials for supercapacitors. However, the low electronic conductivity and small lithium ion diffusion coefficient of V2O5limit its practical applications. To overcome these limitations, a facile and efficient method is here demonstrated for the fabrication of V2O5/reduced graphene oxide (rGO) nanocomposites as electrode materials for supercapacitors. With this method, the reduction of graphene oxide can be achieved in a cost-effective and environmentally friendly solvent, without the addition of any other toxic reducing agent. Importantly, this solvent can control the formation of the uniform rod-like V2O5nanocrystals on the surface of rGO. Compared to pure V2O5microspheres, the V2O5/rGO nanocomposites exhibited higher specific capacitance of537F g-1at a current density of1A g-1in neutral aqueous electrolytes, higher energy density of74.58Wh Kg-1at a power density of500W kg-1and better stability even after1000charge/discharge cycles. Their excellent performances can be attributed to the synergistic effect of rGO and rod-like V2O5nanocrystals. Such impressive results may promote new opportunities for these electrode materials in high energy density storage systems.