[ReadingScience] Survival Strategy in the Lithium War: Replace and Boil Your Battery

German Research Team Develops Process with 75% Lithium Recovery Rate

"Secure the 'white petroleum (lithium)'!"

Countries around the world are currently engaged in a 'lithium war' amid the Fourth Industrial Revolution and the carbon-neutral era. As a core battery material, lithium is indispensable not only for electric vehicles but also for smartphones, laptops, and many other devices. Production is concentrated in a few regions such as China, South America, and Australia. Meanwhile, lithium-poor countries like South Korea are pinning their hopes on battery recycling technology. The problem is that current technologies have low recovery rates and are not economically viable. A German research team has attracted attention by developing a technology that can dramatically improve this.

Lithium mine. Stock photo

On the 27th of last month, a research team from the Karlsruhe Institute of Technology in Germany published a paper in the international journal Nature Communications Chemistry reporting the development of a technology that can increase the lithium recovery rate from existing waste lithium-ion battery recycling processes from the 15% range to the 75% range. This is a mechanochemical process that uses mechanical force to crush or pulverize batteries to trigger chemical reactions.

Batteries contain not only lithium but also expensive rare metals such as cobalt and nickel. Recently, geopolitical crises such as the US-China hegemony competition and the Russia-Ukraine war have made securing battery raw materials a matter of national security for major producing countries including South Korea. Although the supply of these metal materials is not yet critically insufficient, the importance of recycling these metals is growing as energy sources for transportation, such as automobiles, are increasingly replaced by electric charging batteries instead of traditional fossil fuels. In fact, the European Union (EU) has set a goal to recycle 80% of battery lithium by 2031.

Especially in South Korea, where lithium is not produced domestically, the importance of recycling processes that recover raw materials from existing batteries is emphasized. This can reduce environmental pollution caused during mining, processing, and assembly. It is essential in many ways, including cost reduction and resource securing. However, existing lithium recovery processes suffer from significantly poor economic feasibility. They involve heating at high temperatures or dissolving in high-concentration acids or organic solvents before extraction. The lithium recovery rate was only about 15%. The research team first removed the anode material from lithium cobalt oxide batteries, mixed it with aluminum, and then pulverized it into a fine powder. Notably, after grinding this mixture for three hours using a grinder, aluminum reacted with the anode material to form a mixture of insoluble aluminum oxide, cobalt, and water-soluble lithium oxide. After settling this in water and separating it by density differences followed by additional purification, about 30% of lithium was recovered. Although there is still a long way to go to secure economic viability, this recovery rate was twice as high as before.

The research team then made one more modification to this process: they placed the mixture from the grinder into water and heated it. Unlike the previous process, no insoluble lithium aluminum oxide, which is unrecoverable, was formed. As a result, the lithium recovery rate increased to 75%. This was confirmed by testing with various types of lithium-ion battery anode materials.

This mechanochemical method is rarely used in commercial chemical processes. The exact reason why this reaction occurs is still unknown. However, the research team speculates that changes in temperature and friction may have influenced it. The team is working to further improve this process and is also researching methods to simultaneously recover other key metal materials such as cobalt and nickel, in addition to lithium.

Melin, director of Circular Energy Storage, a lithium-ion battery recycling consulting company based in London, UK, told Nature, "This research result is still a laboratory-level success and is more of a proof of principle than a technology that can change the industry landscape." She pointed out, "Battery recycling is more complex than simply developing new technologies and is related to the economics of raw materials and the spread of electric vehicles." She added, "No one knows yet where the lithium we will need in the 2030s will come from."