uhp graphite electrode for arc furnaces
Graphitized carbon nanocage: a new type of sulfur-limited carrier for high-rate and long-life lithium-sulfur batteries
With the development of electric vehicles and portable electronic equipment, human demand for new and efficient energy storage devices is also increasing. As a new type of chemical power source with great potential, lithium-sulfur battery has the advantages of high theoretical energy density, low cost, and environmental friendliness. It has become one of the research frontiers and hotspots in the field of high energy density secondary batteries in recent years.
However, lithium-sulfur batteries still face many problems, including the low electrochemical activity of elemental sulfur, the easy solubility of the intermediate product lithium polysulfide, and the large volume expansion, which greatly restrict the development of lithium-sulfur batteries. In order to solve the above problems, carbon materials are often used as sulfur carriers for the modification of sulfur cathodes to improve the conductivity of sulfur uhp graphite electrode for arc furnaces and inhibit the dissolution of lithium polysulfide.
Traditional graphitized sp2 carbon materials (such as graphene, carbon nanotubes, etc.) have excellent electrical conductivity, mechanical flexibility, and chemical and thermal stability, and are very suitable for use as a conductive load substrate for various types of energy storage uhp graphite electrode for arc furnaces materials. However, studies have found that traditional sp2 carbon materials cannot give full play to their advantages when used as sulfur cathode support materials. Because this type of sp2 carbon generally has a low porosity, when the sulfur-carbon composite is formed, sulfur mainly relies on weak adsorption force to adhere to the surface of the carbon substrate. This is not conducive to the dispersion of elemental sulfur on the conductive carbon matrix; and in the long cycle process, lithium polysulfide is also very easy to diffuse into the electrolyte, causing loss of active materials, which in turn leads to degradation of battery performance.
Therefore, the design and construction of a new sp2 carbon structure to make it an efficient sulfur-carrying matrix is of great significance for the development of high-performance sulfur cathodes. Recently, the research group of Professor Guo Yuguo of the Institute of Chemistry of the Chinese Academy of Sciences has developed a unique sp2-type carbon material with a graphitized carbon nanocage structure and used it as a sulfur carrier for high-rate long-life lithium-sulfur batteries. The carbon material has a three-dimensional sandwich structure, graphene is used as a skeleton, and a sp2-type carbon layer is wrapped around the carbon layer, and graphitized carbon nano-cage structural units are embedded in the carbon layer. The graphitized carbon nanocage is surrounded by several layers of graphitized sp2 carbon, and the diameter of the inner cavity is about 3 to 5 nm. The solution method is used to load the nano-sulfur into the graphitized carbon cage unit. This structure has a large pore volume as a micro-electrochemical reactor for active sulfur. Under the condition of high sulfur loading (77wt%), it can not only realize the high-efficiency dispersion of nano-sulfur, give full play to its electrochemical activity, but also effectively suppress The dissolution and shuttle of lithium polysulfide improves the cycle performance of lithium-sulfur batteries.
In addition, the graphene framework and the highly graphitized carbon nano-cage jointly form a three-dimensional sp2 carbon conductive network with high conductivity and stable structure, which is not only conducive to the high-speed transmission of electrons, but also ensures the stability of the positive electrode structure. The sulfur-carbon composite positive electrode can exhibit a specific capacity of 1375 mAh/g at a current density of 0.1 C, and maintains the capacity at 943 mAh/g after 200 cycles; at a current density of 1 C, the capacity retention rate is as high as 78.4%. At the same time, the uhp graphite electrode for arc furnaces material has excellent high rate performance, and the capacity can still reach 765mAh/g at a current density of 5 C.
The proposal of the graphitized carbon nano-cage structure opens up new ideas for the rational design of a new type of sulfur-carbon composite uhp graphite electrode for arc furnaces material, and opens up new ideas for the development of high-cycle performance, high-rate performance lithium-sulfur batteries and other high-efficiency energy storage devices A new way. When the carbon company was founded, it established the development strategy of “science and technology, innovation, and leadership”, adhering to the business philosophy of “quality first, service first”, through technological improvement, quality improvement, and market development, carbon has become a region in Shanxi, Hebei, and Mongolia. The largest graphitization processing company. The main business is uhp graphite electrode for arc furnaces.