A cycling-insensitive recycling method for producing lithium transition metal oxide from Li-ion batteries using centrifugal gravity separation
2022
Zhan, Ruiting | Pan, Lei
The separation and recovery of electrode active materials from Li-ion batteries is a requisite step prior to any downstream hydrometallurgical and direct recycling processes. Prior research efforts into the separation between the two electrode active materials from Li-ion batteries was limited to the froth flotation process; however, any changes to the surface properties of the active materials resulted in an inferior separation performance. In this work, a novel separation method, namely the Falcon Ultra-Fine (UF) centrifugal gravity concentration, is developed to separate electrode active materials from Li-ion batteries. Results obtained with a mixture of pristine lithium transition metal oxides (LTMOs) and graphite showed that the separation between the two materials perform well with over 90% of LTMOs in the concentrate product after one pass in the UF concentrator. Multiple stages of the separation processes enabled a concentration of LTMOs with 99% purity. Results obtained with aged electrode active materials from spent Li-ion batteries showed that the concentrate product consisted of at least 98% by weight of LTMOs. It was observed that there was a misplacement of LTMOs in the overflow product, which was attributed to the presence of ultrafine LTMOs as well as PVDF-binded cathode agglomerates in the feed. Results of this work demonstrate a viable method for separating mixed electrode active materials and producing high-purity LTMOs, which can be potentially used for the direct recycling of cathode active materials in the manufacturing of new Li-ion batteries.
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