The consumption of rechargeable batteries has exponentially grown since their first commercialization. Of interest, lithium-ion batteries (LIBs) are currently dominating the market, both for stationary and mobile applications. From one LIB to power a cellphone to a pack of six cells in a laptop or thousands in an electric vehicle (E.V.), the number of LIBs currently in use and in need for end-of-life management in the coming years is tremendous. Furthermore, considering the new regulations following commitments to allow for the energy transition, the E.V. market is expected to continue to grow, which implies a surge both in the international battery demand and their end-of-life management. As a sustainable solution, the secondary use of spent E.V. batteries as stationary application may appear as interesting and profitable. However, such a repurposing of spent E.V. batteries for a less demanding application is a short-term answer, as the end-of-life issue remains unsolved as soon as the second life of this battery reaches its end. In addition, the important increase of demand puts pressure on the stock and on the availability of the valuable elements composing the battery (e.g. Lithium, Cobalt, Nickel and Graphite). These minerals currently extracted from mines have recently been classified as “critical” by Canada. For both these reasons, the LIBs recycling became a necessity as it offers several advantages, including: (i) providing a sustainable feedstock of battery components; (ii) avoiding mining of raw limited minerals; (iii) adding value to a system (i.e. the battery pack) that was meant to be discarded; (iv) avoiding the creation of waste.

The focus here will be placed on the recovery and regeneration of the critical minerals that compose the cathode (28% wt) and the anode (22%wt) of a LIB, accounting for 50% of its total mass. LIBs are primarily powered by layered oxides materials composing the cathode (e.g. Li(Ni,Mn,Co)O₂ and Li(Ni,Co,Al)O₂) and graphite composing the anode. At the end of life, the LIBs are usually crushed to obtain a “black mass” from which minerals must be extracted. Nowadays, most of the spent batteries actually end their life in China, where pyrometallurgy is used (i.e. heating up the batteries to high temperature (e.g. 1000°C)) to recover cobalt, and nickel. However, lithium can not be recovered using the pyro-metallurgical process as it will be lost in the slag, as well as aluminium. Graphite is also destroyed in this process. Another technique is hydrometallurgy to recover the valuable metals in solution as well as the graphite as a solid. Moreover, lithium can also be recovered in this recycling process, by precipitation of lithium carbonate but it generates sodium sulfate Na₂SO₄ as an undesired by-product. The latter is costly to eliminate and as no value on the market. This issue, as well as the large acidic wastewater generated by hydrometallurgy will be tackled during this presentation. On one hand, we will highlight our patented sustainable and economical recycling process developed for the recovery of lithium from spent lithium-ion batteries using a new electrochemical technology. On the other hand, we will explain our developments for the recovery of both valuable metals and graphite through a gentle hydrometallurgy process, all towards pushing forward the concept of circular economy. A perspective regarding post-lithium battery technologies will also be given.