The Graphite Anode For Lithium Ion Battery
The graphite anode for lithium ion battery is a key component of the overall battery system. The global market for graphite for batteries is projected to grow to $94.4 billion in 2025, according to Benchmark Mineral Intelligence. As demand for electric vehicles and energy storage grows, the need for high-purity graphite to be used in these batteries is expected to rise.
The anode for lithium ion batteries comes in two forms: natural graphite from mines and synthetic graphite made from petroleum coke. Manufacturers tend to favor synthetic graphite because it is more consistent and has higher purity levels than natural graphite. Regardless of what type of graphite is used, it must be treated to improve its electrochemical properties for use in Li-ion batteries. This is done by thermal treatment to promote intercalation and by chemical purification to reduce impurities.
Graphite’s interlayer distance is too small to allow effective electrochemical intercalation of Na+ ions in untreated graphite (GO). However, the interlayer space can be enlarged by mild oxidation (burning), thereby providing a large enough interspace for efficient intercalation. Mild oxidation also reduces oxygen-containing groups on the GO crystal surfaces and makes it easier for ions to enter the graphite structure.
Using a high-energy vibratory ball mill, spherical natural graphite was mixed with a low-density carbon black and polyvinylidene fluoride (PVDF; Solef 5130) in N-methyl-2-pyrrolidone to form a slurry. The slurry was ball-milled in a stainless vial at 120 °C for 1 h. The morphology of the graphite particles was visualized by a scanning electron microscope (SEM). The improved morphology of the GO resulted in better performance, with a higher rate capability and energy density, lower first cycle irreversible capacity loss and longer cycle life.
