Funktionale Beschichtung von Batteriepulvern. Entwicklung ultradünner Schichten zur Erhöhung der Lebensdauer von Batterien

Functional coating of battery powders - Development of ultra-thin layers to increase the service life of batteries. Two coating processes, atomic layer deposition (ALD) on the one side and wet-chemical spray drying on the other, were selected to provide active materials with protective coatings. Various coating materials were synthesised using both the ALD process and spray drying and investigated in terms of composition and coating thickness and their electrochemical properties. Rate tests and long-term tests of thin Al2O3 ALD layers on LNMO indicate positive effects. For the LNMO sample coated with only 1 nm, the loss is low compared to the uncoated sample. In contrast, 5 nm Al2O3 already shows a considerable isolation of the material. The spray-drying tests of NMC811 with Li2O·WO3 show an accumulation of tungsten on the powder surface and along the grain boundaries after the calcination. The electrochemical rate capability and cycle stability of the active material is significantly improved by coating with 0.5 mol% Li2O·WO3. Scaling up the coating processes ALD as well as spray drying process to a technical scale is considered as possible.