Improved production process with new spheroidization machine with high efficiency and low energy consumption for rounding natural graphite for Li-ion battery applications

Abstract

The demand for rounded graphite for lithium-ion batteries will increase rapidly in the next years, mainly driven by the growing number of electric vehicles. Due to the different particle morphology, synthetic and natural graphite materials have different processing requirements to produce battery-grade materials. However, similar rounding processes with batch-wise operating classifier mills or continuously running classifier mill cascades are used today. For natural graphite in particular, these processes are not very efficient due to their low yield and high energy demand. In this paper, we present a newly developed rounding process for natural graphite, with lower specific energy consumption and higher yield compared to the existing processes. These advantages make the proposed process more economical especially in periods of time with high energy prices. The quality of the material produced by the new process was investigated and compared with the material produced by the existing process, by showing similar graphite properties. Furthermore, the scalability of the new spheroidization process is demonstrated in this paper. Finally, the good cycling performance of the rounded natural graphite material produced by the new process is demonstrated in stacked pouch cells assembled with double side coated anodes. The tested pouch cells still had a capacity retention of over 88% after more than 1000 charge and discharge cycles.