The real cost of our batteries

Nowadays, it is difficult to imagine daily life without using mobile devices, such as cell phones, tablets, or laptops. While our phones are lightweight and capable of lasting throughout the day, this wasn't always the case. These advances are, to a large extent, due to the development of new battery technologies over the years.

The lithium-ion batteries and their widespread use

In mobile applications, lithium-ion batteries (LIBs) prevail due to their high energy density, high output voltage (~3.6 V), and low self-discharge rate (less than 3% per month) [1]. Thanks to these characteristics, most electric vehicles (EVs) use this type of battery. LIBs are also commonly used to support the application of renewable energies by auxiliary energy storage systems [2,3]. Thus, the role of LIBs in reducing greenhouse gas emissions cannot be denied.

The dominant battery chemistry uses lithium cobalt oxide (LCO) as cathode and graphite as anode, but it is not the only one. There are batteries on the market that also use manganese, nickel, and phosphorus, among others.

But what about their ethical implications? pollution, water crisis, and violence

However, the great success and widespread use of this technology are causing several problems around the world, both social and environmental, which represent an even greater challenge. One of them, of course, is to obtain the raw materials necessary for its manufacture, mainly lithium and cobalt, which are obtained, to a greater extent, through mining. These materials, of course, are not renewable.

Obtaining lithium can pose significant problems. For example, in Bolivia, Argentina, and Chile is located the so-called "Lithium Triangle", which contains more than 75% of the supply of this metal worldwide. For extracting lithium from its salt flats, it is necessary to drill into the ground and pump water in order to obtain a brine rich in minerals. Subsequently, this brine is left to dry in the sun; during this process, some substances are added, such as hydrochloric acid, then it is evaporated for up to 18 months to obtain lithium carbonate. This activity consumes enormous amounts of water in a region that is extremely arid on its own, exacerbating the water scarcity that the inhabitants of the area already have to face. On the other hand, leaks can happen in evaporation pools, which causes contamination of the water supply with toxic chemicals [4].

Salar de Uyuni. Image from Alexander Schimmeck, via Unsplash

In other places such as Sichuan province, China, where lithium extraction is done by mining (which is more energy inefficient), this activity has contaminated water bodies, causing the death of cattle and thousands of fish [4].

Cobalt extraction also implies ethical problems; about 60% of the world's cobalt production comes from the Democratic Republic of the Congo. The abundance of a coveted material that is quite scarce in the rest of the world leads, among other things, to a poorly regulated industry, few security measures, high rates of child labor, and an increase in violence [5].

And still, the demand grows

Despite the conflicts that can be generated by the use of these materials, it is expected that by 2050 the demand for lithium and cobalt will increase by 488% and 460% respectively, compared to 2018 [5]. This is due to the goal of decarbonization (using electrifying transportation and creating battery banks for electrical networks), among other factors.

Taking into account that the battery of a compact electric car (for example, the Tesla Model S) uses around 12 kilograms of lithium, it is easy to imagine the problem that we will face in the coming years to meet the demand for lithium and cobalt.

Present and future challenges

With this, another exceedingly important challenge becomes present: the disposal of batteries that have finished their life cycle. Lithium-ion batteries (even small ones, such as cell phone batteries) must be disposed of carefully and correctly, as when they are dumped or illegally disposed of, they can cause landfill fires that are particularly difficult to control, in addition to releasing toxic gases. Also, if a lithium-ion battery leaks, it can release heavy metals and substances such as hydrofluoric acid, which can seep into the subsoil and contaminate water bodies.

On the other hand, this disposition of the batteries does not allow us to recover their components to reuse them. That is why recycling is so important. However, current recycling methods are energy inefficient and use significant amounts of water, and also require storage, which greatly increases the risk of fire in warehouses.

Besides, these processes are economically inefficient, so there is not enough incentive for the industry to invest in infrastructure and make an effort to increase the number of recycled batteries. Currently, only 12% of LIBs in the European Union (one of the best-regulated markets) are recycled, due, among other things, the export of batteries towards Asia. Again, this problem looks set to increase in the coming years, as the first LIBs used in electric vehicles will soon reach the end of their life cycle, leaving behind a need for recycling capacity like never before [3].

What can we do?

Thus, the importance of lithium-ion batteries in our daily lives and the benefits they bring us is clear. However, we cannot ignore that its widespread use implies huge challenges that we must solve. As materials scientists, we can contribute to this by creating cathodic and anodic materials that use less polluting or problematic materials. We can also look for better ways to reuse and recycle them, as well as promote a circular economy that allows us to reduce these intense mineral demands. One exciting initiative is the US Department of Energy's ReCell Center, where academia, industry, and national laboratories collaborate to improve recycling technologies. It is desirable that similar efforts be made around the world, and that all sectors of society give this issue the importance it deserves.

1.     Wu, Y. Lithium-ion batteries : fundamentals and applications. (CRC Press, 2015).
2.     Raw materials for a truly green future. Nature Reviews Materials vol. 6 455 Preprint at https://doi.org/10.1038/s41578-021-00333-9 (2021).
3.     Mrozik, W., Rajaeifar, M. A., Heidrich, O. & Christensen, P. Environmental impacts, pollution sources and pathways of spent lithium-ion batteries. Energy and Environmental Science vol. 14 6099–6121 Preprint at https://doi.org/10.1039/d1ee00691f (2021).
4.     Katwala, A. The spiralling environmental cost of our lithium battery addiction. Wired (2018).
5.     Herrington, R. Mining our green future. Nature Reviews Materials vol. 6 456–458 Preprint at https://doi.org/10.1038/s41578-021-00325-9 (2021).