Method for producing metal borohydride and molecular hydrogen

A method for producing at least one of a metal borohydride and H2, the method comprising the following steps:

• A. producing a metal borohydride in a synthesis process, in which H2 is a reactant, by at least one of:
• A1. providing metal hydroxide, B2O3 and H2 so as to allow the synthesis process to proceed and to yield metal borohydride and O2 according to an reaction formula
• 4Me(OH)n+2nB2O3+6nH2→4Me(BH4)n+5nO2;
• and
• A2. providing metal boron oxide and H2 so as to allow the synthesis process to proceed and to yield metal borohydride and O2 according to an reaction formula
• Me(BO2)n+2nH2→Me(BH4)+nO2,
• in which Me is a metal and n is a valance of a metal ion;
• B. producing H2 in a chemical reaction process, in which the metal borohydride produced in step A and H2O are reactants, the amount of H2 produced in step B, as a result of release from the metal borohydride and H2O, being larger than the amount of H2 required as a reactant in steps A1 and/or A2 for a same amount of metal borohydride as the reactant and the reaction product in steps B and A, respectively;
• and
• C. providing H2 produced in step B to step A, and repeating steps A, B and C,
• wherein a part of at least one of metal borohydride and H2 produced in steps A and B, respectively, is withdrawn while leaving an amount of metal borohydride and H2, respectively, to allow repeating steps A, B and C.