The rapid penetration of lithium-ion technology in the automotive industry, and its interest in network applications due to its low cost, are driving the growth of this technology. This, of course, has numerous consequences for the abundance of materials (Li, Co, etc.) making up the battery. The recycling of Li and the development of alternative technologies based on Na, K, Mg or even Ca are interesting avenues in this context.
This lecture has reviewed the various alkalis and alkaline earths in terms of abundance, while also specifying, in addition to their physico-chemical properties, their redox potential, which is highly dependent on ion solvation, as well as their chemical stability and reactivity. Based on the diagonal rule, the similarity of Li+→ Mg2+ ions in terms of chemical reactivity was highlighted. Being highly reactive, alkaline elements do not exist in their native state in the natural environment, but only in the form of ionic compounds. The development of these compounds by electrocatalysis or chemical means was illustrated, as were the associated fields of application. The role of alkalis in the human body, particularly in nerve impulses, was highlighted. An identical, but shorter, approach was used to describe alkaline earths (Mg, Ca). Finally, the question of recycling was discussed in the context of the growing diversity of metals used, which goes hand in hand with the development of new energy technologies. This leads to greater complexity in recycling processes, which need to be ever more cost-effective. As a demonstration, the recycling of lithium-ion batteries using two processes, pyrometallurgy and hydrometallurgy, which take place at high and low temperatures respectively, was presented. The latter enables Li to be recycled, whereas pyrometallurgy does not.
Finally, the Focus on Recycling concluded with the urgent need to 1) develop new, cheaper and faster recycling approaches, 2) encourage battery manufacturers to integrate recycling constraints into the design of new battery technologies, and 3) alert our government institutions to the need for a recycling policy. The question of who pays for recycling when it is economically unviable will have to be resolved.
