(97a) Recycling of Lithium-Ion Batteries: Selective Leaching of Lithium By Using Water As Sustainable Leaching Agent

Lithium-ion batteries (LIBs) have been a key factor for the breakthrough in electric mobility (e.g., cars) and portable electrical devices (e.g., cell phones and laptops). Lithium is one of the main elements for these batteries owing to its favorable properties (e.g., lightest metal, highest electrochemical potential and highest energy density of all metals). The metal can be extracted from salt lakes and ores, whereby the extraction of lithium from salt lakes requires large amounts of water and is time-consuming (18–24 months). The extraction of ores is an expensive and energy-intensive process. The continuously increasing demand of LIBs will lead to a forecasted lithium shortage of about 47 million tons by 2050, if lithium is not recycled¹. All of these factors lead to the urgent need of developing a recycling concept to recover lithium in high purity. Hydrometallurgical processes have been intensively studied, which have the potential to recycle more than 90 % of spent battery raw materials. However, a major challenge is the different composition of the cathode and anode material. The recycling of valuable metals from LIBs has the advantage that the materials can be directly reused. Within this work, we demonstrate a selective sustainable hydrometallurgical leaching process to recycle lithium using water as sustainable leaching agent.

The selective leaching of lithium from black mass (shredded electrode material, NMC material) is done in batch-mode using pure water without any oxidizing agents. The influence of different process parameters (temperature, solid/liquid-ratio and mixing rate) is investigated. Up to 25 % of lithium can be leached from the black mass in a one-step process.

This process concept corresponds to a promising concept for the direct recycling of lithium carbonate and using it as raw material for new LIBs. Furthermore, the use of strong leaching (e.g., H₂SO₄) and oxidizing agents (e.g., H₂O₂) is minimized and the energy consumption is reduced because no pretreatment takes place. As a next step, the development of a continuously operated process for the selective leaching of lithium will be done.

Sources

[1] Mater. Adv., 2021, 2, 3234-3250