Expandable graphite discovery and development
Discovery and Development
Expandable graphite was first discovered by Schaufautl, a German. In 1841, Schaufautl soaked natural graphite in a mixture of concentrated HNO3 and concentrated H2SO4. After several hours, Schaufautl took it out and dried it.
Union Carbide first patented expandable graphite manufacturing technology in 1963 and began industrial production in 1968.
Common preparation methods
The initial raw material for the preparation of the chemical intercalation method is high carbon flake graphite, and the other chemical reagents such as concentrated sulfuric acid (above 98%), hydrogen peroxide (above 28%), potassium permanganate, etc., are industrial grade reagents. The general steps of preparation are as follows: at the appropriate temperature, different proportions of hydrogen peroxide solution, natural flake graphite, and concentrated sulfuric acid are added in different procedures, and reacted for a certain time under constant agitation, then washed to neutral, centrifugal separation, dehydration, and vacuum drying at 60 ℃.
Electrochemical method: Graphite powder is processed in a strong acid electrolyte to make expandable graphite, hydrolyzed, cleaned, and dried.As a strong acid, mainly sulfuric or nitric acid is used. The expandable graphite obtained by this method has a low sulfur content.
In the process of preparing expandable graphite by ultrasonic oxidation, ultrasonic vibration is carried out on the anodizing electrolyte, and the ultrasonic vibration time is the same as that of anodizing. Because the vibration of ultrasonic electrolytes is beneficial to the polarization of anode and cathode, the speed of anodic oxidation is accelerated and the oxidation time is shortened.
The graphite and intercalator are respectively sent to both ends of a vacuum-sealed tube by the gas phase diffusion method. The intercalator is heated at the end of the intercalator, and the temperature difference between the two ends is used to form the necessary reaction pressure difference so that the intercalator enters between the flake graphite layers in a state of small molecules, thus the expandable graphite is prepared. The number of layers of expandable graphite produced by this method can be controlled, but the production cost is high.
Melt salt method to mix several inserts with graphite and heat them to form expandable graphite.
Expandable graphite Supplier
Luoyang Moon & Star New Energy Technology Co., LTD, founded on October 17, 2008, is a high-tech enterprise committed to the research and development, production, processing, sales, and technical services of lithium-ion battery anode materials.
After more than 10 years of development, the company has gradually developed into a diversified product structure with natural graphite, artificial graphite, composite graphite, intermediate phase, and other negative materials (silicon-carbon materials, etc.).
The products are widely used in high-end lithium-ion digital, power, and energy storage batteries. Feel free to contact us if you need graphite we will reply to you within 24 hours：sales@graphite-corp.com
