Environmental impact of spent lithium-ion batteries and green recycling perspectives by organic acids - A review

The huge usage of rechargeable batteries in electronics has added to a recurrent problem worldwide in generating tonnage of spent lithium-ion batteries (LIBs). The inadequacy of the resources of the depleting critical metals has also been described in vogue. The environmental assessment of the life cycle of the LIBs has been elucidated vis-a-vis the effects of raw material supply, transportation, and recycling. Based on the available work for recycling technologies, this review also attempts to elicit the various methods practiced in discharging/dismantling, classification, and separation of components followed by metal
recovery. The authors have reviewed the major developments in the area of recycling of cathode material by using various acids for extraction of metals from spent LIBs, compared the merits and demerits of acids used and presented a comprehensive outlook to the processes formulated vis-a-vis imperative
need for using green techniques. The necessity for benign recycling methods is stressed upon to alleviate the need for high temperature and oxidative acid leaching conditions. The various green lixiviants (organic acids) attempted to extract metals from spent LIBs have been discussed in detail with respect to the mechanism, efficacies as well as the various factors (selectivity, cost, etc.) that govern the use of organic acids in battery recycling. It was ascertained that the GHG emissions to extract Co using organic acids stand 1/8 of that using an inorganic acid leaching process. Efforts need to be envisaged in separating
the leached metals from these lixiviants ensuring economics and environmental benefits.