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Lithium-ion batteries (LIBs) have an established role in the consumer electronics markets with minimum risk of replacement from any other contender in the near future. The recent momentum towards electric vehicles and the renewable energy storage market is creating an increased demand for LIBs. The large amount of hazardous waste generated from the disposal of LIBs is driving research into a sustainable approach for LIB treatment and recovery. The positive electrode active materials being the main targeted component as it is the greatest cost contributor to LIBs production. During the production of the positive electrode, a powder of active material typically Lithium Cobalt Oxide is applied to aluminium foil and held together using a polyvinylidene fluoride (PVDF) binder. The recovery of positive electrode active material involves physical and chemical treatment. Where effective and efficient physical treatment would reduce the cost incurred for the subsequent chemical treatment. Mechanical treatment is an integral part of liberating and concentrating positive electrode active material. The positive electrode active materials have been reported are being concentrated in the finer size region. However, the cut point at which the positive electrode active material being concentrated is substantially greater than the size of the positive electrode active material particle size as found in spent LIBs. This paper studies the characteristics of milled spent LIBs concerning particle size. The results suggest that a cut point of 850 µm gives the best composition of the positive electrode active materials recovery that minimises the involvement of copper and aluminium. However, most of the active materials are still held together by the PVDF binder that creates a substantially higher cut point proposed that the actual size of the positive electrode active material contained within spent LIBs. The interaction of copper and aluminium current collector based on size also further discussed in this paper. A comparison between selective liberation in the new and spent LIBs has been made to assess the difference in mechanical properties that contribute to its overall liberation efficiency.

Highlights Attrition scrubbing is effective in selectively concentrating LiCoO2. Attrition scrubbing improves liberation efficiency from 34% to 77%. Attrition produces a precursor for hydrometallurgical processes. Electrostatic separator is used to recover copper and aluminium. AbstractIn this manuscript, the results show that the single-stage liberation by using a cutting mill is sub-optimum. From the analysis, that the size fraction of < 850 µ m only recovers 43.7 wt% LiCoO2. With the recovery of 9.0 wt% aluminium and 10.6 wt% copper the remainder of the copper being in the > 850 µ m size fraction. The low recovery of LiCoO2 is caused by the particles that are still adhering on to the surface of the aluminium current collector. This lack of liberation prompted the use of attrition scrubbing as a secondary stage of mechanical treatment. 2.5 min Attrition scrubbing improves the selective liberation of cobalt towards aluminium and copper by 36.6 % and 42.6 % respectively. Attrition induces abrasion and it is shown to liberate the LiCoO2 particles. Results show a minimum of 80 wt% LiCoO2 particles can be recovered in the size fraction of < 38 µ m with 7.0 wt% aluminium 2 and 6.1 wt% copper recovery, making attrition scrubbing a suitable second stage mechanical treatment for the recovery of LiCoO2.

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