Graphite As An Anode in Lithium-Ion Batteries
Whether it is a smartphone, laptop or electric car - Lithium-ion batteries are the power source that powers our daily lives. In order to meet the required performance parameters for a battery, it is necessary to increase the amount of active materials in the same volume of the cell (anode and separator). Graphite is a natural choice because of its electrochemical properties in combination with low manufacturing costs and long cycle life.
However, one of the major barriers to large scale adoption of LIBs is poor rate capability caused by first cycle irreversible capacity loss due to reductive electrolyte decomposition and lithium consumption (see figure below).
To reduce this degradation and improve the performance of graphite in Lithium-ion batteries it has been shown that by modifying the morphology of the graphite particles, improvements can be made in both the coulombic efficiency and the first cycle irreversible capacity.
In order to achieve this, it is necessary to create a barrier that prevents direct electronic contact between the graphite and the electrolyte. This can be achieved by coating the graphite with a material such as wax, linseed oil or resin. The impregnation also serves as a protection against moisture intrusion that can lead to anode failure.
This is particularly important for high cycle life applications where the anode is exposed to elevated temperatures. The insulating layer also improves the anode’s performance during fast charging by preventing the formation of lithium dendrites.
