Lithium, the new white gold for the green transition?

Christel Laberty-Robert, head of the RMES¹ team at the Paris Condensed Matter Chemistry Laboratory (in French) and a specialist in batteries and materials chemistry, sheds light on the importance of this ubiquitous metal in our daily lives, the production of which is controversial.

What are the characteristics of lithium that make it so important in batteries?

Christel Laberty-Robert: Lithium is a solid, light metal with a high electrochemical potential. Because of these properties, it enables the development of compact batteries with high energy densities that can be used in cell phones or electric vehicles.

As an essential element in the digital and energy transitions, lithium is also used, to a lesser extent, in other applications: thermonuclear fusion, mood-regulating drugs, and the manufacture of certain alloys, ceramics and glass.

In what form does it exist naturally and how do we extract it?

C. L.-R.: Lithium is not very concentrated in the earth's crust and is found in ionic form in ores such as silicates (particularly spodumene), which must be extracted in very large quantities to manufacture batteries. Extraction processes are time-consuming, energy-intensive and require large quantities of water and chemicals.

Lithium is also present in brines, notably in Argentina and Chile. To extract it, these brines are pumped to the surface and then stored for several months until the water evaporates. They then undergo chemical and physical treatments to produce lithium carbonate and hydroxide.

Where are the main deposits in the world, in Europe and in France?

C. L.-R.: They exist mainly in South America and Australia. There are also some in the United States, Brazil and Portugal. Although China does not have large reserves, it has taken an interest in the process of extracting lithium and transforming it into oxides (lithium hydroxide and carbonate), which are used to manufacture batteries.

In Europe, deposits have been identified in Germany, Austria, Portugal, Finland and Serbia. In France, three areas have been identified: in the Armorican massif, in the Rhine valley and in the northern part of the Massif Central where the world's leading industrial minerals company, Imerys, plans to open a mine by 2027. This mine project, which would require an investment of nearly one billion euros, would produce enough lithium to equip 700,000 electric vehicles per year for at least 25 years from 2028.

What are the world's future lithium requirements over the next 20 years?

C. L.-R.: According to the International Energy Agency, the annual volume of lithium mined worldwide has tripled since 2015 and demand for lithium is expected to increase by 40% by 2040 due to the concomitant initiation of the energy transition by many countries. According to a study published by the University of Leuven, lithium needs in Europe in 2050 will be 35 times greater than today.

In Europe, the construction of gigafactories, the giant battery factories for electric vehicles, will generate very high metal demands. As a result, the European Commission has listed lithium as a critical raw material in 2020.

What is the environmental impact of lithium mining?

C. L.-R.: Mining changes the nature of the landscape and produces considerable volumes of potentially polluting waste. It requires the use of sulfuric acid and other chemicals that can contaminate the environment. Explosions in mines cause clouds of smoke to be released into the atmosphere. All these processes are also very energy intensive. The extraction of lithium from brines involves very large quantities of water: about 2 million liters of water to produce one ton of lithium.

These impacts are known, but their importance is underestimated in Europe because most of the production takes place outside the continent. It is important that Europeans, who are major consumers of lithium, ask themselves about the secondary effects of its extraction in order to have a complete vision of the impact on the environment. The opening of mines on our territory should enable a societal awareness of what our lifestyles imply in environmental terms.

Are lithium batteries recyclable?

C. L.-R.: Although battery recycling does exist, it is not yet automated due to the lack of standardization of battery packs. It is therefore important for manufacturers to think about a circular economy that will enable them to design batteries that can be easily disassembled and recycled by automated disassembly lines.

In addition, a lot of work needs to be done to optimize the recycling processes, which are currently long and energy-consuming. The battery pack must first be discharged before its various modules are dismantled and crushed to recover the black mass in an inert atmosphere. The lithium must then be extracted using hydro-metallurgy or pyro-metallurgy processes.

Once the recycling process has been optimized, used batteries could constitute an urban mine of lithium and other critical elements in Europe.

What are the alternatives to lithium?

C. L.-R.: The Electrochemical Energy Storage Network (RS2E) is working on sodium batteries, which are two to five times more powerful than lithium batteries. They have several advantages, including the fact that they can be charged much more quickly and stored without a charge. Unlike lithium batteries, they are made from an element that is found in large quantities in nature and is much less expensive to extract. Prototypes of these batteries are beginning to be developed by the RS2E startup Tiamat, with a view to opening a larger factory in the next few years.

In addition, the development of low-cost, greener aqueous batteries based on non-critical metals will be a challenge in the years to come. This is a major challenge for a rapid energy transition on all continents.

Are you involved in strategic research programs related to lithium?

C. L.-R.: My team is involved in two major projects currently supported by the government. The first, led by RS2E, brings together public and industrial players to address energy storage issues. It gave rise to the second: a priority research equipment program (PEPR) to develop new battery technologies, in particular all-solid state batteries. Other Sorbonne University laboratories, such as PHENIX², (link in French)are working within RS2E on other lithium-related topics, including battery recycling processes.

^{1 Reactive Materials for Electrochemical deviceS}

^{2 Physicochemistry of Electrolytes and Interfacial Nanosystems (Sorbonne Université/CNRS)}