Graphite As an Anode and Cathode in Lithium-Ion Batteries
Graphite is one of the most important components in lithium-ion batteries, serving as both the anode and cathode. It has dominated as an anode since the inception of Lithium-ion batteries, thanks to its unrivaled balance of low cost, abundance, high energy density, power density and very long cycle life.
The atomic structure of graphite results in three out of the four electron shells not being fully bonded, allowing them to migrate between layers of the crystal lattice and create large free electrons (also known as graphene). These free electrons make graphite an excellent conductor. It’s also cheap, hard-wearing and highly stable at high temperatures, adding to its versatility as an electrode material.
In lithium ion batteries, the positive charge moves from the anode to the cathode through the electrolyte. This process involves lithium ions being intercalated into, or inserted into, open spaces within the graphite, a process called “intercalation.”
Aluminum GDIBs work in a similar way to lithium, sodium and potassium GDIBs: reversible oxidation and intercalation of aluminum species occur on both the anode and cathode during charge. However, the intercalation mechanism in aluminum GDIBs is different due to the varying van der Waals and ionic repulsion between and within the graphene layers. This unique staging mechanism provides the aluminum GDIBs with a significant advantage over traditional graphite-based Li-ion batteries.
We recently spoke with John DeMaio, President of Graphex’s Graphite Division and CEO of Graphex Technologies, about why graphite is essential for the battery industry. He explains how graphite’s production and applications are changing to keep pace with EV demand, as well as why there are still no substitutes for its performance as an anode material.