Abstract: In order to carry out a selective extraction of cations (Mn+) by an electrochemical transfer in a solution from a first electrolyte (E1) to a second electrolyte (E2), the method includes using as an electrolyte separation wall a transfer wall (2) made of chalcogenide with molybdenum clusters (MonXn+2 or MxMonXn+2) and ensuring the cation transfer through the transfer wall by generating a potential difference (?E) between the electrode A1 in the first electrolyte (E1) and the electrode C2 in the second electrolyte (E1) or the transfer wall (2) in order to induce an interleaving of the cations in the transfer wall on the side of the first electrolyte, a scattering of the cations therein, and the de-interleaving thereof in the second electrolyte.