1. Cascade utilization and raw material recycling
Retired power lithium-ion batteries that are used in a tiered manner will be recycled after being used in a tiered manner; those that are directly recycled are those with too small a batch, no historical records, or those that fail safety monitoring, etc.
The pursuit of economic benefits is a driving force behind corporate and societal behavior. In theory, the tiered utilization of lithium-ion batteries, reducing their usable value to below maintenance costs, before recycling them as raw materials, maximizes battery value. However, in reality, early power lithium batteries suffered from poor traceability and inconsistent quality and models. The tiered utilization of early batteries carried significant risks, and mitigating these risks was costly. Therefore, it can be said that in the early stages of power lithium battery recycling, the primary destination for these batteries was likely raw material recovery.
2. Methods for extracting valuable metals from cathode materials
Current discussions about recycling power lithium-ion batteries do not actually cover the comprehensive recycling and reuse of all materials used in the battery. Important cathode materials include lithium cobalt oxide, lithium manganese oxide, ternary lithium batteries, and lithium iron phosphate batteries.
The cost of positive electrode materials accounts for more than one-third of the cost of a single battery cell. Since the negative electrode currently uses more carbon materials such as graphite, and lithium titanate Li4Ti5O12 and silicon-carbon negative electrode Si/C are less commonly used, the current battery recycling technology mainly focuses on the recycling of positive electrode materials.
There are three main categories of recycling methods for spent lithium-ion batteries: physical, chemical, and biological methods. Compared with other methods, hydrometallurgy is considered a more ideal recycling method due to its advantages such as low energy consumption, high recycling efficiency, and high product purity.
3. Hydrometallurgy
Hydrometallurgy is a method that uses suitable chemical reagents to selectively dissolve the cathode material in spent lithium-ion batteries and separate the metal elements from the leachate. Hydrometallurgy is well-suited for recycling spent lithium-ion batteries with relatively simple chemical compositions. It can be used alone or in conjunction with high-temperature metallurgy. It has low equipment requirements, low processing costs, and is a mature method suitable for small to medium-scale recycling of spent lithium-ion batteries.
