Production of Nickel-Rich Cathodes for Lithium-Ion Batteries from Lab to Pilot Scale under Investigation of the Process Atmosphere

The selection of an appropriate cathode active material is important for operation performance and production of high-performance lithium-ion batteries. Promising candidates are nickel-rich layered oxides like LiNixCoyMnzO2 (NCM, x+y+z=1) with nickel contents of 'x' >= 0.8, characterized by high electrode potential and specific capacity. However, these materials are associated with capacity fading due to their high sensitivity to moisture. Herein, two different polycrystalline NCM materials with nickel contents of 0.81 <= 'x' <= 0.83 and protective surface coatings are processed in dry-room atmosphere (dew point of supply air T-D approximate to -65 degrees C) at lab scale including the slurry preparation and coating procedure. In comparison, cathodes are produced in ambient atmosphere and both variants are tested in coin cells. Moreover, processing at pilot scale in ambient atmosphere is realized successfully by continuous coating and drying of the cathodes. Relevant electrode properties such as adhesion strength, specific electrical resistance, and pore-size distribution for the individual process steps are determined, as well as the moisture uptake during calendering. Furthermore, rate capability and cycling stability are investigated in pouch cells, wherein initial specific discharge capacities of up to 190 mAh g(-1) (with regard to the cathode material mass) are achieved at 0.2C.