Possibilities of exploitation of useful metals from used Li-ion batteries

The paper presents the possibilities of recovering cobalt from used batteries. Given the evolution of the electric car market, the demand for cells of those raw materials for batteries such as cobalt, nickel, lithium will increase in the coming years. Efforts must be made by all actors involved to meet these needs in a sustainable manner. The recycling of used batteries involves the utilization of valuable elements present within them. Electric car batteries are part of the circular economy in which battery materials are recovered and reused to produce other batteries. Recycling is important because it reduces the pressure on the demand for raw materials.


Introduction
Currently, the car market is made up of two large categories of vehicles [1]: -Conventional vehicles (ICE); -Alternatively-powered vehicles (APVs) present in table 1.The evolution of new car sales in the EU is shown in Figures 1 and 2. There is a decrease in sales of conventional vehicles and an increase in alternative vehicles.Given the increase in the number of electric cars on the car market, it can be considered that batteries are placed at the center of this transition in the field of clean mobility systems [2].A very important influence on the demand for batteries is also manifested by an increase in the market demand for electric vehicles intended for passenger transport.
Battery manufacturing and recycling at the end of life has become a priority and a strategic goal for many regions of the world, especially China and the EU [2], [3].Although there are currently different types of batteries, Li-ion batteries [1], [2], [3], [4] are estimated to dominate the electric vehicle market for at least another decade.
The required materials [2], [5] Li-ion battery manufacturing are: lithium, cobalt, nickel, graphite, etc.The demand for lithium, cobalt and graphite will increase by about 500% by 2050 [1], [2] taking into account the evolution of the market.The resources of these materials are found in few regions of the world, mainly in Argentina, Chile, Bolivia and the Democratic Republic of Congo [6].Battery The Li-ion battery consists of a group of interconnected cells.A cell consists of the following (figure 3): a graphite anode with a copper collector, a cathode consisting of a metal oxide with an aluminum collector, separator and electrolyte.The chemical composition of the cathode defines the type of Li-ion battery: NCA, NMC, LMO, LFP, LTO.

Figure 3. A Li-ion battery [2]
There are currently other types of batteries / production technologies under development and testing.The largest Li-ion battery factory is Tesla Gigafactory 1 Nevada followed by four factories in China.Europe has a battery production growth rate of over 10% by 2030 [2], [7], [9], [10].
Currently, battery recycling has a number of problems: technological limitations, recycling efficiency limitations, low recycling rates, lack of material collection and recovery infrastructure.Recycling also has an impact on the environment through the emergence of other waste, high energy consumption and greenhouse gas emissions.Europe is making financial efforts to increase battery production but also to streamline their recycling process.Some of the financial resources are used for research and innovation in the production and recycling of batteries [9], [10].Battery recycling focuses mainly on the elements: cobalt, lithium, aluminum, copper, manganese.

Experimental researches
The process of recovery and recycling of used batteries involves life cycle (figure 4): -Obtaining materials (extraction, preparation, processing, refining); -Manufacture of battery components; -Manufacture of batteries; -Equipping and using batteries on electric cars; -Recycling.The paper presents the research carried out in the laboratory phase on the possibilities of capitalizing on cobalt in the form of pigment from used Li-ion batteries.
The technological flow of cobalt recovery in the form of pigment is presented in figure 5.
Li-ion batteries from electric vehicles were used for laboratory research.They were dismantled manually and the content was separated on components (cathode, housing, contacts, foils).
Figure 6 shows the aspects during the dismantling of the batteries.Figures 7 and 8 show the components of the dewed batteries as well as an average of them.
Only the battery cathode was used to recover the cobalt.Ultrasound was used for the cathode paste cleaning process on the aluminum cathode.The tests and equipment used are shown in figure 9.The recovery yield of the active paste is calculated as follows [8]: where:  0 is the initial mass of the cathode film (Al+paste foil);  is the final mass (Al foil), after ultrasonication in acidic medium (acetic acid).
The results obtained are presented in figure 10.

Conclusions
Because cobalt is an non-renewable resource, its recycling is a strategic issue.The solution presented in the paper proposes the capitalization of cobalt in the form of pigment.Cobalt blue is an inorganic pigment consisting of a cobalt aluminate spinel.The presented method of recovering cobalt in the form of a pigment is a viable and environmentally friendly method.The method involves the manual disassembly of the batteries and the recovery of the cathode paste in an ecological environment.The resulting cathodic paste is used for pigment production.Cobalt side sources are very valuable.Disposable Li-ion batteries have a high cobalt content.The obtained cobalt blue is a pigment used in various industrial sectors.

Figure 1 .Figure 2 .
Figure 1.Trends over time in the EU (in units, 2017-2021) for conventional vehicles on Applied Sciences (ICAS 2023) Journal of Physics: Conference Series 2714 (2024) 012018 IOP Publishing doi:10.1088/1742-6596/2714/1/0120183 manufacturing, in addition to the consumption of poor raw materials, also requires large amounts of energy and generates carbon and waste emissions.

Figure 10 .7
Figure 10.The efficiency of the cathode paste recovery operation