More economical and more environmentally friendly! Germany develops new process for preparing battery electrodes

Introduction: The Fraunhofer Institute for Materials and Beam Technology (IWS) in Germany has developed a dry coating process that does not require the use of toxic solvents in the production of battery electrodes and is more environmentally friendly.

Electrodes are the core components of batteries and usually consist of metal foil covered with a thin coating. Most traditional processes for making battery electrodes involve toxic solvents and require a lot of space and energy.

Fraunhofer IWS has developed a dry coating process called DRYtraec that is environmentally friendly and cost-effective, can be used on a large scale, and has the potential to revolutionize the manufacturing of battery electrodes in the future.

Benjamin Schumm, group leader for chemical coating processes at Fraunhofer IWS, explains: “Conventional coating processes use a wet-chemical method. A slurry made of active material, conductive carbon black and binder together with a solvent forms a wet layer on the foil. This requires extremely large machines with very long drying tracks to ensure that the solvent evaporates afterwards. With DRYtraec, we can design this process much more efficiently.”

The dry coating process at Fraunhofer IWS does not use solvents but relies on a special binder. Together, the materials form a powder that is placed in the calender gap, i.e. the gap between two rollers that rotate in opposite directions. One of the rollers rotates faster than the other. This generates a shear force that ensures that the binder forms a network of threads, the so-called cellulose. "Imagine it like a spider's web, which is mechanically embedded in the particles," says Schumm. Through pressure and movement, a fine film is formed on the rapidly rotating roller, which is then transferred to the conductive film in the second calender gap.

Schumm stressed that the technology is not limited to a specific battery chemistry and can be used in lithium-ion batteries as well as lithium-sulfur or sodium-ion batteries , and even in solid-state batteries.

According to the institute, negotiations are currently underway with several car and battery manufacturers to realize various pilot plants.