Elizaveta Kogut*
Moscow South-Eastern School named after V.I. Chuikov
*Email:
The story of lithium-ion batteries began in the late 1970s and early 1980s when scientists sought to develop improved batteries capable of storing more energy while being lighter than their predecessors, such as nickel-cadmium batteries. In 1976, a chemist, John B. Goodenough, made a significant discovery by identifying cobalt oxide as a viable positive electrode for a battery. This breakthrough paved the way for innovative battery designs. In the 1980s, another scientist, Akira Yoshino, built upon Goodenough’s research and created the first practical lithium-ion battery (Orangi et al., 2024). He utilized petroleum coke as the negative electrode and LiCoO2 as positive electrode, which enabled the battery to charge and discharge efficiently, making it ideal for use in electronic devices. In 1991, Sony commercialized the first lithium-ion battery for consumer products, such as camcorders. This marked a transformative moment in battery technology; these batteries were lightweight, boasted a high energy capacity, and could be recharged multiple times. Since then, lithium-ion batteries have become the standard power source for a wide array of electronics, including smartphones, laptops, and electric vehicles. Researchers continue to enhance this technology, focusing on improving safety, longevity, and efficiency. Today, lithium-ion batteries are integral to many devices and play a pivotal role in the shift toward renewable energy and electric transportation.
The demand for lithium has more than doubled over the past eight years, primarily due to the growth of lithium-ion batteries, which now represent a market valued at $40 billion. Lithium is extracted from minerals and brines; however, the extraction processes are complex and energy-intensive. From 2018 to 2019, lithium consumption surged by 18%, raising concerns about the potential depletion of existing lithium reserves. Consequently, technologies to recycle lithium from used lithium-ion batteries are currently being developed (Orangi et al., 2024).
The process begins with a pre-treatment stage, where the batteries are carefully collected and dismantled. During this stage, case materials (plastic, Al, Cu) are removed, and the batteries are sorted to prepare them for further processing. Once the batteries have undergone pre-treatment, the next step is to extract valuable metals, primarily lithium, along with cobalt, nickel, manganese, titanium, and others. There are three main methods used to extract these metals: pyrometallurgical, electrochemical, and hydrometallurgical methods.
- Pyrometallurgical Method: This method involves incinerating battery materials at high temperatures to recover metals. Although it is effective in separating certain metals, it can also consume a significant amount of energy and may release harmful gases such as phosgene, dioxins, carbon monoxide into the environment.
- Electrochemical Method: This approach utilizes electric currents to drive chemical reactions that separate the metals. While promising, this method is still under development and may not yet be widely adopted for industrial-scale recycling.
- Hydrometallurgical Method: This method is regarded as the most efficient and environmentally friendly option available. In the hydrometallurgical process, solvents or acids are utilized to dissolve valuable metals from battery materials. This approach enables the selective recovery of lithium as well as other metals such as cobalt, nickel, and titanium, making it a highly effective way to recycle battery materials and a sustainable choice in the long run.
There are three main methods for recovering metal ions from the solutions formed during the recycling process: precipitation, absorption, and solvent extraction.
- Precipitation involves adding chemicals to the solution to form solid particles of metals, which can then be filtered out. This method is straightforward but may not effectively separate different metals.
- Absorption uses materials that can grab onto the metal ions in the solution. While this method can be effective, it often requires specific conditions and can be less efficient for certain metals.
- Solvent extraction is one of the most effective methods for separating metals, especially heavy metals, in solution. In this process, organic solvents are used to selectively bind with specific metal ions. This allows for a more precise separation of metals like lithium, cobalt, nickel, titanium and others.
Hydrophobic deep eutectic solvents (HDES) are a promising new type of water-immiscible solvent that was introduced in 2015. They offer several advantages over traditional ionic liquids, including easy synthesis, variety of possible components, adjustable physicochemical properties, and selectivity. As a result, research on HDES has significantly increased over the past decade. They are a mixture of two or more components, when mixed, a eutectic point is formed, that is, the melting point of the HDES is lower than that of the initial components. The eutectic point appears owing to the formation of hydrogen bonds between the donor (HBD) and acceptor (HBA). The figure shows the most common classes of substances used as components of the HDES (Osch et al., 2020).
In my research, I studied the extraction of titanium ions contained in lithium-titanium anodes using the HDES Aliquat 336/Menthol. The decision to use HDES based on Aliquat 336 was influenced by a previous study where another group (Quinn et al., 2013) of scientists successfully extracted Ti(IV) ions using the extractant Alamine 336, which shares similar extraction properties with Aliquat 336. Therefore, we assumed that the extraction of Ti(IV) ions by this HDES will also be highly effective. Menthol, on the other hand, serves as a safer alternative to toxic and highly flammable organic solvents. Its inclusion in the extractant enhances safety and environmental friendliness. Furthermore, the addition of menthol lowers the concentration of Aliquat 336, subsequently reducing the viscosity and cost of the extractant. The key parameters that affect the extraction process were varied, and a method for the selective extraction of titanium ions from leachate solutions using this HDES was proposed.
In conclusion, by utilizing the knowledge and methods discussed in this article, we can efficiently recycle lithium-ion batteries. This not only helps recover valuable materials, such as lithium, titanium and others, but also contributes to reducing the environmental impact. Implementing these techniques allows us to create a more sustainable approach for battery disposal and resource management.
References
Bae, H., & Kim, Y. (2021). Technologies of lithium recycling from waste lithium-ion batteries: A review. Materials Advances, 2(5), 1428–1440. https://doi.org/10.1039/D1MA00216C
Kim, T., Song, W., Son, D.-Y., Ono, L. K., & Qi, Y. (2019). Lithium-ion batteries: Outlook on present, future, and hybridized technologies. Journal of Materials Chemistry A, 7(7), 2942–2964. https://doi.org/10.1039/C8TA10513H
Makoś, P., Słupek, E., & Gębicki, J. (2019). Hydrophobic deep eutectic solvents in microextraction techniques – A review. Microchemical Journal, 149, 104384. https://doi.org/10.1016/j.microc.2019.104384
Orangi, S., Manjong, N., Perez Clos, D., Usai, L., Burheim, O. S., & Strømman, A. H. (2024). Historical and prospective lithium-ion battery cost trajectories from a bottom-up production modeling perspective. Journal of Energy Storage, 73, 109800. https://doi.org/10.1016/j.est.2023.109800
Quinn, J. E., Wilkins, D., & Soldenhoff, K. H. (2013). Solvent extraction of uranium from saline leach liquors using DEHPA/Alamine 336 mixed reagent. Hydrometallurgy, 134–135, 74–79. https://doi.org/10.1016/j.hydromet.2013.01.007
Van Osch, D. J. G. P., Dietz, C. H. J. T., Warrag, S. E. E., & Kroon, M. C. (2020). The curious case of hydrophobic deep eutectic solvents: A story on the discovery, design, and applications. ACS Sustainable Chemistry & Engineering, 8(26), 10591–10612. https://doi.org/10.1021/acssuschemeng.0c00559
