A rechargeable electrochemical metal ion cell includes negative and positive electrodes, and an electrolyte system between them. The negative electrode includes a metal capable of releasing and accepting metal ions. The positive electrode includes at least one compound capable of releasing and accepting metal ions different from those of the negative electrode. The electrolyte system includes: a glycol-based electrolyte solution containing a salt of a metal included in the negative electrode and a salt of a metal included in the positive electrode; a matrix adapted to retain the electrolyte solution, where two reversible reactions take place simultaneously in the cell: a reversible deposition and dissolution process of ions of a metal included in the negative electrode takes place in the negative electrode and a reversible ion exchange process of a metal included in the positive electrode takes place in the positive electrode. The metals are different from one another.