Recycling lithium-ion batteries with the extraction of valuable materials is a complex business. However, over the past ten years, the depletion of metal reserves is forcing manufacturers to act proactively without waiting for shortages and rising prices.
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Why is Recycling Li-Ion Batteries Needed?
Waste in the form of used lithium-ion batteries is a valuable resource. The natural resources of elements, lithium and cobalt, in Li-ion batteries are depleting, and access to these resources is critical for everyone today.
The issue of battery disposal is relevant for environmental institutions and health authorities. The recycling of Li-ion batteries is the only way to maintain the ecological balance as batteries often end up in landfills. This endangers the environment and human health as damaged batteries release toxic elements and gases, and if stored uncontrolled, they become explosive.
Challenges of Recycling Lithium-Ion Batteries
One of the problems with recycling lithium batteries is their possible ignition. If the Li-ion battery is disposed of with household waste, then even a small charge in the battery is likely to ignite. In addition, the internal environment of the battery consists of a solution of hydrochloric acid, which is dangerous for organic matter.
The Li-ion batteries must be de-energized and dismantled in traditional recycling methods. Here, the main problem of all existing methods of recycling arises - the fire and explosion safety of lithium, which requires the creation of special conditions for dismantling. In addition, all recycling methods are characterized by high energy consumption and significant losses of raw materials.
Current Methods of Recycling Lithium-Ion Batteries
Physical recycling method
The most common recycling technology is the physical recycling method of lithium-ion batteries. Its essence lies in the destruction of the integrity of the cell with the help of special equipment equipped with a shutter mechanism and the manual selection of materials that require further recovery.
All this work must occur under specially maintained temperature and humidity conditions due to the risk of fire and explosion hazard of the battery during the process. Moreover, due to the non-automation of the process, this method has low productivity and a constantly varying value of the amount of recoverable material.
Hydrometallurgical method
The hydrometallurgical process, which involves pretreatment, leaching, and metal separation, effectively recycles used lithium-Ion batteries. However, for hydrometallurgy to be cost-effective, a minimum amount of extraneous material must be exposed to the process.
As a result, hydrometallurgical processing will not recycle materials such as electrolytes, polymers, or casings. Modules are securely dismantled to a controllable size. The modules or cells are then comminuted to generate a free-flowing material, which is then subjected to physical separation processes to isolate the electrode coatings and concentrate the cathode materials.
Pyrometallurgical method
In the pyrometallurgical method, the plastic, electrolyte solution, and graphite electrode are burned in a furnace to maintain the melting point. The final secondary products - the anode active compound metals and lithium are in the slag composition, further used as an additive in concrete. However, it is not possible to isolate lithium in its pure form with this technology.
Recent Breakthrough: Making New Batteries from Old Ones
The Princeton NuEnergy team has proposed a method that recovers most of the structure and composition of the used cathode, cobalt, and lithium from the used Li-Ion batteries.
The team's method is based on the usage of low-temperature plasma, an extraordinarily reactive ionized gas. In addition, since used batteries lose some lithium from the cathode material over time, Princeton NuEnergy adds a trace amount of lithium to the regenerated cathode powder, resulting in a less expensive material than brand new cathodes.
At the Wistron Greentech site in McKinney, Texas, Princeton NuEnergy is currently constructing a process line. Due to this agreement, the company hopes to raise output to at least one ton per day by 2022.
Princeton NuEnergy's use of cold plasma can be used in various applications. As a result of these plasma generators, biologically active species such as reactive species (both radical and nonradical), charged particles and photons, and electric fields are generated. There is considerable potential for cold atmospheric pressure plasmas to remove a variety of dangerous substances related to food, environmental, and medical technology and medicine.
The Future of Recycling Batteries
Current methods of recycling lithium-ion batteries typically place the batteries at the end of their useful life in a shredder or high-temperature reactor. These recycling routes are energy-intensive and inefficient. By taking an alternative approach and disassembling batteries at the end of their useful life instead of shredding them, there is the potential to make new batteries from the old ones.
Cathode materials are sourced from China, which is the world's leader in battery recycling. Because of this, components must be moved worldwide to be recycled, increasing the carbon footprint of recovered batteries and decreasing their appeal as a more sustainable option.
The Princeton NuEnergy team's strategy eliminates a major portion of international commerce and transportation needs, paving the way for other nations to boost local battery recycling.
Future Developments
In Europe and the USA, regulations are being implemented that will require battery manufacturers to fund the costs of collecting, storing and recycling all collected batteries. In addition, appropriate process chains are already being created to ensure the environmentally efficient management of used lithium-ion batteries.
To date, recycling is not considered a priority for battery manufacturers. The recycling issues should be considered at the product design stage. This will create a viable, scalable recycling scheme in line with the circular economy principles.
References and Further Reading
Hojnik, N., Modic, M., Walsh, J., & Cvelbar, U. (2021, October). Cold Plasma As a Tool for a Removal of the Harmful Contaminants. ECS Meeting Abstracts (No. 15, p. 669). IOP Publishing. https://iopscience.iop.org/article/10.1149/MA2021-0215669mtgabs
Lohani, A. (2020). Recycling Li-ion batteries: Opportunities and challenges. [Online] Observer Research Foundation. Available at: https://www.orfonline.org/expert-speak/recycling-liion-batteries-opportunities-challenges-68409/. (Accessed on 26 March 2022).
Seltzer, N. (2022). A better way to recycle lithium batteries is coming soon from this Princeton startup. [Online] Princeton University. Available at: https://www.princeton.edu/news/2022/03/01/better-way-recycle-lithium-batteries-coming-soon-princeton-startup (Accessed on 28 March 2022).
Zhou, L. F., Yang, D., Du, T., Gong, H., & Luo, W. B. (2020). The current process for the recycling of spent lithium ion batteries. Frontiers in Chemistry, 1027. https://doi.org/10.3389/fchem.2020.578044
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