Regeneration of NCM811 after separation from the decanter centrifuge

Currently, several processes exist for the recycling of lithium-ion batteries (LIBs). The pyrometallurgical approach, for example, is robust and safe, but the achievable recycling rate is limited, especially with respect to certain elements and starting compounds (or precursors). In contrast, the mechanical approach promises potentially higher recycling rates, but comes along with higher safety risks, and material separation in the crushing process is only moderately selective.

Herein, we present an overview of the latest results of the HydroLIBRec project, which is funded by the German Federal Ministry of Education and Research within the Competence Cluster Recycling & Green Battery (greenBatt). The core and unique feature of the HydroLIBRec LIB recycling process is the expected high material selectivity in the comminution steps, the preservation of the functional materials, and the use of water in most of the processes to ensure high safety. One of the novel methods in HydroLIBRec is the continuous fractionation of black mass by robustly controlled decanter centrifuges. Decanter centrifuges are also suitable for fractionation of particulate structures at high throughputs and are established and available in the industry for different throughputs. Thus, this process step is easily scalable. However, Ni-rich layered oxide cathode materials with low Co content and high specific capacity such as NCM811 (LiNi_0.8Co_0.1Mn_0.1O₂) are extremely sensitive to water and moisture. Therefore, regeneration of the cathode material is required after the water-based decanter centrifuge process. Preliminary results on the regeneration of NCM811 (LiNi_0.8Co_0.1Mn_0.1O₂) via a hydrothermal process after separation from a decanter centrifuge will be presented. Moreover, the electrochemical data obtained for the regenerated cathode material will be discussed in detail.