Graphite As the Anode Material in Lithium-Ion Batteries
The anode is the critical component in lithium-ion batteries that power our portable electronics, longer range electric vehicles and other energy storage applications. Lithium ions are stored in the anode via intercalation (insertion into open spaces) of carbon, which is usually in the form of graphite. The ions are then transported to the cathode for discharging and recycling.
Currently, the anode in most commercial battery technologies uses natural flake graphite or a blend of coated spherical graphite and synthetic graphite. Graphite’s unique physical structure enables it to absorb and transport the lithium ions between its layers during charging and discharging. It is a critical material in current anode designs and has been the primary anode material in lithium-ion batteries since their introduction in 1940. The material’s capacity has remained relatively unchanged over the years and is the best available.
The main challenge for battery makers is to find an alternative material that can meet the higher performance requirements of new lithium-ion anode designs. Silicon is one of the leading candidates as it can offer much higher gravimetric and volumetric capacities than graphite. However, it is still a work in progress.
A few companies have developed next-generation anode materials that use silicon and metals instead of graphite, but they are not yet ready for mass production. The good news is that several companies have made significant progress in improving the quality of natural graphite to make it more suitable for lithium-ion battery anodes. Among them are Vancouver-based Ceylon Graphite, which recently completed full cell testing with its spherodized vein graphite material in commercial size pouch cells following automotive standards.
