Resynthesis of NCM 811 cathode active material from recycled nickel sulfate via fed-batch coprecipitation

Circular resource concepts are of increasing relevance for cathode active material (CAM) like lithium nickel cobalt manganese oxide (NCM) for lithium-ion batteries (LIBs) due to its high production cost and its significant environmental impact. Therefore, there are substantial efforts to set up a circular economy for CAM. This includes its recovery from end-of-life batteries and its processing to starting materials. The recovery is currently still performed on a small scale and the feasibility of resynthesizing CAM needs to be investigated. This work aimed to demonstrate process compatibility of high-purity recycled NiSO 4 with fed-batch coprecipitation for NCM 811 resynthesis. The objective was to show that comparable physicochemical and electrochemical properties can be achieved when substituting primary NiSO 4 entirely with recycled NiSO 4 . For this, we used recycled NiSO 4 from an industrial supplier as well as commercially obtained primary NiSO 4 to comparatively conduct the synthesis of NCM 811 on a laboratory scale via hydroxide coprecipitation, followed by a drying step, lithiation and a high-temperature calcination process. The synthesized products were characterized with physical and chemical analysis methods such as XRD, ICP-OES and SEM as well as with electrochemical testing to compare the influence of recycled NiSO 4 on the product properties to the influence of primary NiSO 4 . The main result of this work is that the fed-batch-resynthesis of NCM 811 CAM from recycled NiSO 4 was successful since comparable CAM properties were achieved with the use of primary and recycled NiSO 4 .