The invention relates to an energy converter cell, consisting of a negative metal electrode, preferably a tin electrode, a positive electrode consisting of graphite and an electrolyte that is positioned between the electrodes and is in contact with the latter, the electrolyte containing in the charged state a manganate(IV) salt that is dissolved in water and an alkali hydroxide. The energy converter cell forms a galvanic element, which can be discharged by delivering electrical energy to an ohmic consumer resistor that is connected to the electrodes and can be charged by a supply of thermal energy. In addition, supplied electrical energy can be electrochemically stored in the cell.