The elements that make up the cathode materials in lithium-ion batteries vary depending on the required performance, which has been continuously evolving through improvements in energy density, for example. However, even if the cathode material generates a large amount of energy, the energy would not be efficiently used when the anode material, which is responsible for storing the energy, cannot handle it. Also, the better the anode material receives lithium ions, the shorter the charging time will become. This achievement would be felt more by users than they would with any advancement involving cathode materials. Anode materials have such an important role to play. Let’s look at the current development landscape of the anode materials.
The anode generates electricity by storing the lithium ions from the cathode (+) and releasing them back. For a long time, graphite (natural graphite and artificial graphite) has been used as an anode material. It has a regularly layered structure that allows lithium ions to enter and be stored. However, as the performance and capacity of batteries advance, there is a growing need for a next-generation anode material that would allow the batteries to charge rapidly.
The emerging next-gen anode material after graphite is silicon. Graphite stores one lithium ion for every six carbons, while silicon stores 4.4 lithium ions for every silicon atom. In other words, silicon anode has four times more capacity per gram than graphite anode. Silicon will be able to extend the driving range of electric vehicles by dramatically improving energy density. It can also make designing rapid charging of batteries easier than using graphite. At the same time, silicon is economical and eco-friendly, which makes it a more attractive candidate as a next-generation anode material.
Experts project that the anode material market for rechargeable batteries would grow as the electric vehicle market expands. The silicon anode market, in particular, is expected to grow significantly. According to market research firm SNE Research, the silicon anode market will be worth 5.6 trillion won in 2025, a massive jump from 15.5 billion won in 2020.
However, there are still looming problems involving silicon anode materials, particularly the volume expansion that takes place during lithiation and the tendency to break. These are major hurdles to overcome. Nevertheless, in 2019, LG Energy Solution applied a 5% silicon anode to a pure electric vehicle for the first time in the world. It is currently pushing to apply a 7% silicon anode for the first time globally. As LG Energy Solution continues to innovate its technologies, look out for more of the company’s successful advancements.