What is the high-temperature and high-pressure graphitization method used in a high-temperature graphitization furnace? Let’s take a look:
A graphitization furnace uses bituminous coal as a precursor. After preliminary carbonization, the material is further graphitized at 2,000–2,800°C to produce synthetic graphite. Research shows that the microstructure of synthetic graphite strongly depends on the graphitization temperature. When artificial graphite is graphitized at 2,800°C, it develops a completely ordered layered structure, with high graphitization degree, larger surface area, and well-developed mesopores. This provides an excellent pathway for lithium-ion embedding and extraction in carbon-based anodes.
Because graphite has high temperature resistance and high strength, it is widely used in the smelting industry for manufacturing graphite crucibles and furnace linings. More importantly, graphite has excellent electrical conductivity, making it suitable as an electrode material and a base material for composites, enabling high-value applications in advanced technology.
Graphite also features high reversible capacity, good conductivity, stable charge-discharge potential, and relatively low cost, so it is widely used in energy-storage devices. For example, petroleum coke graphitized at 2,600°C reaches a graphitization degree of 78.8%. When used as an anode material for lithium-ion batteries, it delivers a discharge capacity of 326.1 mAh/g with a Coulombic efficiency of 78.8%, demonstrating excellent electrochemical performance.
Using two types of anthracite with different properties, graphite was prepared by thermal treatment in a high-temperature graphitization furnace at 2,400–2,800°C, and its electrochemical properties as a lithium-ion anode were tested. The graphite materials produced from both types of anthracite showed a fairly good linear correlation in crystal parameters. This method enables batch production of graphite with good crystallinity at high temperature.
However, it also comes with drawbacks:
- Requires temperatures above 2,000°C → high energy consumption
- The exhaust and waste generated during graphitization can cause air pollution
- It has strict raw material limitations — it is mainly suitable for graphitizable carbon materials such as petroleum coke and pitch coke, where carbon atoms already form layered structures.
Materials like resin carbon or glassy carbon have porous turbostratic structures and cannot be graphitized, even above 2,000°C.