The economical, environmental and geopolitical context recently pushed Europe to issue a regulation on battery recycling. By 2031, 80% of lithium in batteries should be recovered. In this context, CEA is interested in Electrochemical Lithium-Ion Pumping (ELIP): this process uses battery electrodes to selectively insert and disinsert lithium, allowing to extract it from a complex solution. Unlike more common lithium recovery processes, ELIP allies a high selectivity towards lithium, does not require the use of toxic chemicals during the process and offers the possibility to be used in a continuous flow mode, practical for industrial applications. A first PhD work on the subject, in our team, evidenced for the relevance of such a process for the separation of lithium from other alkali cations (sodium and potassium). Real battery leachates are however more complex and can include transition metal cations and organic species besides alkaline cations. The proposed PhD subject has the aim to precisely understand the effect of these solutions on the ELIP process in order to choose the best position in the recycling loop (upstream or downstream), and to adapt to adverse effects encountered in such conditions. The impact of the other species present in solution will be evaluated on selectivity, efficiency and durability at different scales: material, electrode and membrane. Chemical (ICP-AES, EDX), structural (XRD) and morphological (SEM, TEM) characterizations will be correlated with electrochemical results in order to identify side reactions and species which impact the most the performances. Based on these results, the PhD student will have to test different improvement protocols (additive incorporation, pH control, change of the electrochemical method, etc...) and to understand the physico-chemical reasons governing these improvements. The PhD work will allow to propose a thoughtful integration of the ELIP process in conventional battery recycling steps, as well as highlighting the relevance, or not, of such a process for lithium extraction from real leachates.