Natural Swedish Graphite for Future Lithium-ion Batteries

Important results from the project

The aim of the project is to study whether natural graphite produced by Woxna Graphite AB can function as an anode in a lithium-ion battery. Therefore, using temperature as a means to clean the graphite from impurities is studied. At what temperature will natural graphite become so pure that it can be used as a negative electrode? The battery capacity of the graphite should be equal to that of synthetic graphite which is 350 A / kg compared to the theoretical of 372 Ah / kg. If electrodes can be fabricated in a way to improve fast charging by enabling lithium ions to quickly enter into the graphite

Expected long term effects

The most important thing is that the natural graphite is suitable as anode material. It needs to be cleaned at high temperatures: 2300°C is needed for several hours for small amounts of graphite, but for large amounts the temperature needs to go up to 2800°C. When freeze drying is used to make electrodes, the speed of lithium graphite intercalation can increase. The next step is to scale up electrodes and that Woxna Graphite AB can perform temperature purification. Work continues in the Vinnova competence center for batteries.

Approach and implementation

The project has two stages. Stage 1: Woxna has provided graphite purified to 99% to UU, which has studied how residual contaminants are affected by heat treatment at two temp.: 1000°C and 2300°C. Chemical analysis has been carried out on the treated samples. The samples have been studied as an anode in lithium job batteries. Various methods have studied the morphology as well as particle orientation in electrodes. Stage 2 focuses on electrodes where particle orientation is influenced to give faster lithium intercalation. Ambitious project that needs more time and better oven.