Biotechnological Applications in Spent Lithium-Ion Battery Processing

Lithium-ion batteries (LIBs) have emerged as the leading energy source for a diverse array of electronic devices, owing to their numerous benefits. Recycling LIBs is of significant importance since the ever-growing demand for them will shortly lead to massive disposal of spent LIBs and cause critical environmental problems. Spent LIBs can be considered as an excellent secondary source for various valuable metals since they approximately contain Mn (5–11%), Co (5%–25%), Ni (5%–10%), Li (5%–7%), Al (15–20%), Cu (5–7%), and graphite. Currently, LIBs’ recycling is mainly through the pyrometallurgical or high-temperature hydrometallurgical approaches, which have been substantiated to be effective for metal extraction. However, these processes come with some disadvantages such as inefficient energy consumption, high operational cost, toxic gas emission and production of secondary hazardous waste. The application of bio-hydrometallurgical methods has demonstrated remarkable efficacy in extracting metals from ores, flotation concentrates, tailings, and diverse waste materials. As an eco-friendly, low-cost, and energy-efficient method, bioleaching can be a superior replacement for conventional LIB recycling processes. In this chapter, new trends of LIB bioleaching, various factors influencing the LIB bioleaching, mechanisms, microorganisms, and regeneration of black mass have been thoroughly discussed. Moreover, the dominant challenges for industrial application of LIB bioleaching and several approaches for upscaling were summarized.