Recycling Lithium Batteries

Lithium-ion batteries are currently the most widely used electrochemical energy accumulators, particularly in the fields of electronics and electric vehicles. Their high energy density by mass and volume, and excellent cycling performance, make them the most suitable systems for supplying mobile energy at the lowest possible cost.

Their consumption is set to increase tenfold over the next ten years, due to the development of electric vehicles. But this raises the question of the availability of raw materials, which will have to be recycled if the world's resources are not to be exhausted. The development of battery manufacturing plants in Europe also poses the problem of local resource supply. The recycling of lithium batteries represents a major challenge for our industrial development in the years to come, as it reduces the risk of supply.

Unfortunately, recycling these products can be dangerous, due to the risk of explosion or fire, and the toxicity of the metals treated. Initially, we limited ourselves to simple methods such as pyrometallurgy, which eliminates waste while recovering only the most expensive metals (cobalt, nickel) and the most easily recoverable, for re-injection into the metallurgy industry. But these methods are energy-intensive, and other elements see their value rise sharply. Also, the growing flow of used batteries makes the emergence of closed-loop recycling (from batteries to batteries) economically viable. The constraints will therefore be to recycle more batteries in greater numbers, and to improve the recycling rate of each battery by exhaustively recovering all the elements for reuse in new batteries. However, battery manufacture requires high-purity products, whose separation-purification and remanufacturing sequences will have to be adapted to obtain a completely closed cycle. Finally, standardization will enable complex, robotized recycling sequences, including part-by-part recovery of cells for repair or regeneration, before re-injecting them into new batteries (direct recycling).

It is therefore necessary to understand the risks and particularities of battery recycling, and the avenues open to us to achieve more virtuous recycling that is less costly in terms of energy, emissions and completeness.

This article will discuss the constitution of lithium batteries, then review complementary techniques for dismantling, heat treatment (pyrometallurgy) and solution separation routes (hydrometallurgy). The future objective is to design batteries that can be easily recycled, with exhaustive recovery of all elements, and the methods of recovery by separations and regenerations without totally destroying the materials (direct recycling) will finally be presented as perspectives.