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Interview with Laida Otegui, Researcher at CIC energiGUNE


Could you explain the difference between dry and wet processing and why GIGAGREEN’s innovations are key for the improvement of these two processes?

The main differences between dry and wet processing on battery manufacturing are mainly devoted to electrode fabrication. Wet processing electrode manufacturing consists of anode/cathode slurry (active materials, additives, binder, and solvent) coating on top of a current collector and subsequent solvent drying. On the contrary, dry processing techniques avoid the use of any solvents for electrode preparation and the components are dry mixed and adhered to the current collector with the action of pressure and temperature.

Currently, the state-of-the-art electrode fabrication procedures are based on wet processes. Anode slurry formulations are usually water based, but cathode slurry formulations are based on N-Methyl-2-pyrrolidone (NMP), which is flammable, expensive, toxic and has recently been included to the restricted substances list by the European Commission. With the aim to avoid the use of NMP, to reduce costs and improve sustainability, two alternative approaches for electrode manufacturing will be developed in GIGAGREEN. First, aqueous based cathode formulations will be developed. This will avoid the need of expensive NMP recovery systems after the drying zone. Secondly, dry processing will also be evaluated. This approach, not only is expected to reduce drying times, avoid volatile fumes, solvent recovery, and recycling systems, but also will allow for improved cell energy and power density by enabling unique dense high loading electrode microstructures. For both the approaches, materials such as binders, active materials, separators, and current collectors will be developed and optimised in GIGAGREEN project.