The parameters of graphite mainly include physical, chemical, thermal, electrical, and mechanical properties. These indicators reflect the composition, structural characteristics, and practical performance of graphite materials. Common physical parameters include density, hardness, porosity, particle size, and specific surface area. The theoretical density of graphite is approximately 2.26 g/cm³, and its Mohs hardness is typically 1–2, but different types of graphite products may exhibit significant differences in actual density and mechanical properties. Chemical parameters mainly include fixed carbon content, ash content, volatile matter, sulfur content, and the content of other impurity elements. Fixed carbon content is one of the important indicators for evaluating the quality of graphite raw materials. Generally, a higher carbon content means relatively fewer mineral impurities, but the specific quality still needs to be judged in conjunction with other testing indicators. Particle size and specific surface area affect the processing performance, reactivity, and application effects of graphite, and are particularly important in the production of battery anode materials, lubricating materials, and conductive materials.
The thermal and electrical parameters of graphite are also important bases for evaluating its technical performance. Thermal parameters mainly include thermal conductivity, coefficient of thermal expansion, heat resistance, and thermal shock resistance. The thermal conductivity of graphite is affected by crystal structure orientation, density, purity, and manufacturing process, thus significant differences may exist between different graphite materials. The coefficient of thermal expansion reflects the degree of dimensional change of the material after heating, while thermal shock resistance relates to graphite's ability to resist cracking under rapid heating or cooling conditions. Electrical parameters mainly include resistivity, conductivity, and dielectric properties. Resistivity is a frequently considered indicator when selecting graphite electrodes, conductive components, and battery materials; generally, the lower the resistivity, the stronger the conductivity. Due to the significant anisotropy of graphite, its electrical and thermal parameters may change with the measurement direction; therefore, the test direction and specific conditions must be clearly defined to ensure data comparability.
In industrial applications, mechanical properties and chemical stability of graphite also require attention. Mechanical performance parameters mainly include compressive strength, flexural strength, elastic modulus, wear resistance, and impact resistance. These indicators directly affect the load-bearing capacity and service life of graphite products during actual operation. Chemical stability parameters are typically evaluated through oxidation behavior, corrosion resistance, and performance changes after contact with specific media. For example, graphite used in high-temperature furnaces and metallurgical equipment requires particular attention to oxidation resistance, high-temperature resistance, and thermal expansion characteristics; graphite used in lithium-ion battery anodes requires attention to specific capacity, initial coulombic efficiency, cycle life, rate performance, and particle size distribution. Therefore, there is no single parameter table applicable to all graphite products, and the requirements for material performance vary depending on the application. In actual material selection and quality testing, appropriate testing items should be selected based on the type of graphite, the usage environment, and industry standards, and a comprehensive evaluation should be conducted based on specific test data.
