Influence of Graphitization on the Properties of Anode Materials

Influence of Graphitization on the Properties of Anode Materials

Graphite has become one of the core raw materials of lithium-ion batteries because of its good electrical conductivity, suitable for the intercalation-deintercalation layered structure of lithium, and good cycle performance. In recent years, artificial graphite, natural graphite and composite graphite have been widely used. With the rapid development of lithium-ion new energy vehicles, the advantages of artificial graphite in rate and cycle characteristics have become increasingly prominent, and it has become the mainstream raw material for power batteries. At the same time, its cost has received extensive attention and has become a research hotspot.

The production process of artificial graphite anode material mainly includes the following 4 parts: crushing of raw materials; surface modification of powder particles; graphitization; screening and magnetic removal and packaging. In recent years, with the maturity of domestic needle coke technology and the expansion of scale, the cost of graphitization has exceeded the cost of raw materials, which has become an urgent problem to be solved.

The main equipment for the graphitization of the negative electrode material is the Acheson furnace. Referring to the electrode graphitization process, the powder is loaded into the graphite crucible. Due to the effect of resistance, the carbon powder is heated and heated at a temperature of 2500~3000 ℃. into artificial graphite.

However, the energy consumption of the Acheson graphitization furnace itself is relatively high, only 30% of the electric energy is used for the graphitization of products, and it is also accompanied by the emission of harmful gases, which requires expensive supporting environmental protection facilities. The graphitization process consumes a lot of auxiliary materials and has high cost pressure.

The box graphitization is based on the Acheson graphitization furnace. A carbon plate box is set in the furnace, which is equivalent to enlarging the size of the crucible. Using the box and materials to generate heat can greatly reduce energy consumption and increase production capacity. The graphitization of the box has developed rapidly, the technology has become more mature, and the process can be automated, accounting for more than 20% of the market share;

Continuous graphitization is a new technology developed in recent years. It adopts resistance or induction heating, and the maximum temperature can reach more than 3000 ℃. It can realize continuous feeding and discharging at high temperature, reduce energy consumption, shorten production cycle, and realize on-site operation.