PUBLISHER: SNE Research | PRODUCT CODE: 1230334
PUBLISHER: SNE Research | PRODUCT CODE: 1230334
Currently, graphite is mostly being used as an anode material for lithium secondary batteries. It means that from 1991 - when Sony firstly commercialized lithium secondary batteries - until now, graphite has firmly maintained its throne of anode materials. This has nearly been steadfast even for the last 20 years, while other materials, including cathode materials, separation membranes, etc, have changed.
Graphite is largely divided into natural and artificial graphite. Raw ores of natural graphite are yielded with graphite containing about 5-15% in graphite mines. In order for graphite to be used as an anode material for lithium secondary batteries, it must obtain the purity of at least 99.5% as a battery grade. To increase the purity up to such a degree, the dug natural graphite ore should go through beneficiation, chemical processing, etc. to remove impurities. It can sometimes be spheroidized and pitch-coated.
Artificial graphite, on the other hand, is the graphite generated by heating carbon precursors, such as petroleum, coal tar, and coke, whose starting materials are not natural minerals, at the high temperature higher than 2800°C.
Other than graphite, other anode materials include soft carbon and hard carbon, which are manufactured by heat-treating coke, consisting of carbon, at 1000-1200°C, relatively low temperature. Of these, hard carbon has had increasing importance as an anode material for EVs due to its excellent power characteristics.
For the composite-based, LTO, the oxide composite-based, is representative, and the metal composite-based includes Sn-Co-C and others. In addition, in the case of an anode using graphite, an electrode is sometimes manufactured by partially mixing silicon- and SiOx-based compounds with graphite to increase capacity.
In order to increase the energy density of Li secondary batteries, research on Li-metal as the ultimate anode material is also being conducted, and it is expected that Li metal is mainly used as an anode material for all solid batteries (ASBs), the next-generation battery.