Due to the rapid pace of product upgrades in consumer electronics and the continued promotion of lithium-ion batteries in the electric vehicle sector, a large number of waste lithium-ion batteries have emerged in recent years.
The huge market demand for lithium-ion batteries will lead to a large number of waste batteries in the future. How to deal with these waste lithium-ion batteries in order to reduce their environmental impact is an urgent problem to be solved. On the other hand, in order to meet the huge market demand, lithium-ion battery manufacturers need to produce a large number of lithium-ion batteries to supply the market.
In the pretreatment stage, how to safely and efficiently achieve automatic dismantling of waste lithium-ion batteries is a major obstacle to the industrial recycling of waste lithium-ion batteries; how to systematically recycle and reuse the various components in waste lithium-ion batteries, and how to reduce or prevent these secondary pollutions, all require further in-depth research.
Lithium-ion battery material recycling technology
The recycling process of spent lithium-ion batteries mainly includes pretreatment, secondary treatment, and advanced treatment. Since spent batteries still retain some charge, the pretreatment process includes deep discharge, crushing, and physical sorting. The purpose of secondary treatment is to completely separate the positive and negative electrode active materials from the substrate, commonly achieved through methods such as thermal treatment, organic solvent dissolution, alkaline dissolution, and electrolysis. Advanced treatment mainly includes leaching and separation purification processes to extract valuable metal materials.
Based on the extraction process, lithium-ion battery recycling methods can be mainly divided into three categories: dry recycling, wet recycling, and biological recycling.
1. Dry recycling
Dry recycling refers to the direct recovery of materials or valuable metals without the use of solutions or other media. Important methods used include physical sorting and high-temperature pyrolysis.
2. Wet recycling
The wet recycling process involves crushing and dissolving waste batteries, then using appropriate chemical reagents to selectively separate metal elements from the leaching solution, producing high-grade cobalt metal or lithium carbonate, which are then directly recycled. Wet recycling is well-suited for recovering waste lithium-ion batteries with relatively simple chemical compositions. Its equipment investment costs are relatively low, making it suitable for small to medium-scale waste lithium-ion battery recycling. Therefore, this method is currently widely used.
3. Biological recycling
Mishra et al. used inorganic acids and Acidobacterium ferrooxidans to leach metals from spent lithium-ion batteries, and used S and ferrous ions (Fe2+) to generate metabolic products such as H2SO4 and Fe3+ in the leaching medium.
Lithium-ion battery recycling technology
1. High-temperature metallurgical method
Waste lithium-ion batteries that have undergone simple mechanical crushing and are roasted at high temperature are then screened to obtain fine powder containing metals and metal oxides.
2. Hydrometallurgy
After the waste batteries are crushed, they are selectively dissolved using appropriate chemical reagents to separate the metal elements in the leachate.
