South Korean researchers have developed a new production technology for dry electrode batteries, which could increase the range of electric cars, shorten charging times and reduce production costs.
The development is underwritten by the Korea Institute of Materials Science and the Korea Electrotechnology Research Institute, and the solution refers to anodes with specially shaped graphite granules. The goal is to overcome the limitations of existing dry electrodes, especially with thicker structures that can store more energy.
Dry production of electrodes has long been seen as an important direction of development for the battery industry, as it bypasses the classic process with a liquid mixture, chemical solvents and large industrial furnaces. This reduces energy consumption, shortens the production line and mitigates the impact on the environment.
Dry battery electrodes use graphite granules instead of PTFE binder
The problem until now has been PTFE, a bonding material better known as Teflon. It binds the particles in the dry electrode, but it belongs to the group of PFAS materials and can create major environmental and technical problems. Because of this, the researchers tried to replace it with the standard CMC-SBR binder, which is already used in common battery production.
Replacing the binder alone was not enough. Classic anodes use plate-like graphite particles that stack like a deck of cards when pressed. Such a structure hinders the movement of lithium ions, because they have to bypass the layers instead of passing directly through the electrode.
The new solution uses a process of spraying and drying a mixture of graphite, conductive additives and binders. Thus, rounded composite granules are formed in which the graphite sheets are randomly turned in different directions.
Such an internal structure allows lithium ions to move in multiple directions, instead of encountering flat barriers. The result is better diffusion of ions, which is especially important with thicker electrodes intended for batteries with a higher energy density.
According to the researchers, the developed dry anode showed better rapid charging and more stable operation during long cycles compared to conventional anodes obtained by the liquid mixture process. The technology is published in the journal Energy Storage Materials. The advantage is that it relies on CMC-SBR binders that are already known to the industry, so the existing factories would not have to completely change their production lines.
If the technology is successfully transferred from the laboratory to mass production, dry battery electrodes could lead to electric cars with longer range, shorter charging times and cleaner production of battery cells, IE writes.