The introduction of Lithium-ions(Li-ion) batteries has been as revolutionary to humanity as the discovery of plastic. Lithium-ion batteries are everywhere, from our mobile phones to now our cars and energy storage systems. The biggest push towards the adoption of Li-ion batteries has primarily been its free-falling costs.
In an earlier article, we established that we have more than enough lithium to satisfy our needs. But just like plastics, the biggest issue with li-ion batteries can arise once they have completed their service life. The good news is that like solar panels, batteries too can be recycled! However, it may not be as straightforward a process.
Why Recycle?
One of the greatest issues driving lithium-ion battery recycling is one of waste management – but it is not correct to say that all of the batteries being manufactured today are headed for landfill. When a lithium-ion battery comes to the end of its life, it still retains around 80% of its charge[1] – and while that’s not enough to serve an electric vehicle, it’s good enough for a variety of different applications, such as energy storage. These second-life batteries could be used for at least 10 years[2].
Since these batteries often contain valuable materials such as nickel, manganese and cobalt[3], to eventually dump them in landfill as volumes of waste increase would be a waste of precious resources. A solid recycling infrastructure would also slow depletion of the critical cobalt reserves necessary to manufacture these batteries[4], it’s estimated that by 2030, recycling could provide Europe with 10% of its cobalt supply[5]. That provides the industry with an added benefit of relying less on problematic sources: at least 60% of the world’s cobalt is mined in the Democratic Republic of the Congo[6], where some of the most vulnerable in society bear the brunt of its extraction – cobalt mining in DR Congo is linked to human rights abuses, such as child labour and armed conflict[7].
The Difficulty with Li-ion Recycling
Much of the recycling that does take place today is done through a combination of pyrometallurgy and hydrometallurgy[4]. While the process recovers some of the most valuable metals in the Li-ion battery, much of the other valuable material is lost. When a battery is thrown into a smelter, you get a mixture of alloys out the bottom – typically nickel, cobalt and copper. The lithium and aluminium get oxidised and go to the slag, which is not economical to recover. After the lithium and aluminium gets sent to landfill, the only thing we are left with are the metal alloys. These then have to be treated hydrometallurgical to extract the maximum value, breaking down the cathode’s crystal structure and leaching the different ions out of the battery to end up with the precursor salts like nickel sulfate and cobalt sulfate which you can use to manufacture new batteries[8].
Numerous issues complicate the development of a more efficient process. A fundamental problem is that these batteries simply aren’t designed to be recycled, they’re designed for high-performance and longevity. A lithium-ion battery pack is made up of several thousand cells grouped in modules, with each cell containing a cathode, anode, separator and electrolyte. Cathodes generally consist of an active transition metal oxide powder mixed with carbon black and glued to an aluminium-foil current collector with a compound such as poly(vinylidene fluoride) (PVDF). The anodes contain graphite glued to a copper foil with PVDF, and the electrolyte is usually a solution of LiPF6 salts. In a nutshell, they are not designed to be taken apart and recycled, causing major problems[8].
Another major issue is that there is no standard design or chemistry followed in the industry. These factors make it extremely difficult to justify the costs associated with the recycling process.
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References
[1]: Tomaszewska, et. al, “Lithium-Ion Battery Fast Charging: A Review”. eTransportation. 1. 100011. 10.1016/j.etran.2019.100011, 2019
[2]: Canals Casals, Lluc & García, Beatriz & Canal, Camille “Second life batteries lifespan: Rest of useful life and environmental analysis”, Journal of Environmental Management. 232. 354-363. 10.1016/j.jenvman.2018.11.046., 2019
[3]: Recycle spent batteries. Nat Energy 4, 253 (2019). https://doi.org/10.1038/s41560-019-0376-4, April 2019
[4]: Beaudet, Alexandre; Larouche, François; Amouzegar, Kamyab; Bouchard, Patrick; Zaghib, Karim. 2020. “Key Challenges and Opportunities for Recycling Electric Vehicle Battery Materials” Sustainability 12, no. 14: 5837. https://doi.org/10.3390/su12145837
[5]: Kumagai, Jean. (2021). Momentum Builds for Lithium-ion Battery Recycling: The goal is to prevent thousands of tons of spent batteries from going to waste. IEEE Spectrum. 58. 52-53. 10.1109/MSPEC.2021.9311427.
[6]: https://www.washingtonpost.com/graphics/business/batteries/congo-cobalt-mining-for-lithium-ion-battery/
[7]: Banza Lubaba Nkulu, Célestin et al. “Sustainability of artisanal mining of cobalt in DR Congo.” Nature sustainability vol. 1,9 (2018): 495-504. doi:10.1038/s41893-018-0139-4
[8]: https://www.chemistryworld.com/features/the-drive-to-recycle-lithium-ion-batteries/4012222.article
