ELECTROCHEMICAL PROCESS FOR THE PRODUCTION OF PRESSURIZED GASEOUS HYDROGEN BY ELECTROLYSIS THEN DEPOLARIZATION

An electrochemical process comprises a step El of electrolysis of an electrolyte in order to produce gaseous oxygen and a step of converting oxidation-reduction chemical energy into electrical energy with production of H2. The electrolyte comprises Mm+ ions of a metal M corresponding to the redox pair (Mm+/M), and Aa+ ions of a depolarization additive A corresponding to a redox pair (Aa+/A). Current is supplied between the anode and the cathode, Aa+ and Mm+ are deposited on the cathode respectively in the form of A and M during the electrolysis and gaseous oxygen is released at the anode. The supply of current between the anode and the cathode is then cut off. Depolarization occurs corresponding to the conversion step C°, with production of H2 and dissolution of M and A into Mm+ and Aa+ at the electrode acting as the cathode during step El and the produced H2 is collected.