70 percent lithium yield through new battery recycling process
Already now, ever larger quantities of discharged batteries are accumulating from old electric cars and many other uses such as smartphones, tablets and toys. With the upcoming energy transition, this number will continue to rise. At the same time, there is an increasing need to recycle the raw materials they contain, as their extraction is often complex and very expensive. This is especially true for lithium, which does not occur in isolation in nature. This makes it all the more important to recover the material from old batteries.
With the processes commonly used to date, the materials cobalt, nickel, aluminium, copper and steel are the most commonly recycled. The recovery of lithium with the mostly metallurgical processes available to date, on the other hand, still causes high costs and is often very energy-intensive. Some of the processes (additionally) produce environmentally harmful by-products.
A new process for recovering lithium from spent batteries, which is currently being developed at the Karlsruhe Institute of Technology (KIT), offers three advantages: It is environmentally friendly, cost-effective and energy-efficient. The process promises to recover up to 70 percent of the raw material and is based on a combination of chemical reactions and mechanical processes.
In the new method, chemical reactions are brought about by means of mechanical processes; it was developed in a cooperation between the Institute for Applied Materials - Energy Storage Systems (IAM-ESS) of KIT with the Helmholtz Institute Ulm for Electrochemical Energy Storage (HIU) and EnBW Energie Baden-Württemberg, whereby the Helmholtz Institute Ulm is in turn based on a cooperation between the University of Ulm and KIT.
As Dr. Oleksandr Dolotko, lead author of the paper on the new process published in Nature Communications Chemistry, explains, it can be used to recover lithium in a way that is both energy and cost efficient and also avoids the use of corrosive chemicals. Another advantage of the method, says Dolotko, who works at IAM-ESS and HIU, is the reduced effort required upstream of recycling: The materials do not need to be sorted beforehand.
One process for different cathode materials
Since the new recycling method of lithium can be applied to cathode materials with different chemical compositions, it can also be used flexibly with numerous commercially available lithium-ion batteries. In the mechanochemical reaction, the aluminium contained in the cathode is used as a reducing agent – so no additional material needs to be added.
The reaction process is very simple
In the process, the collected old batteries are ground up in a first step. Then, by means of a reaction with aluminium, metallic composites are created that have water-soluble lithium compounds. After these are dissolved in water and the water is then heated until it evaporates, the lithium is finally recovered. The mechanochemical reaction process is extremely simple and also particularly energy-efficient, as the reaction takes place at room temperature and pressure.
Source: elektronikpraxis.de, Thomas Kuther, 28.03.2023