A method for preparing a material adapted for reversible storage of hydrogen, comprising the successively performed steps of: (a) providing a first powder of a magnesium-based material; (b) hydrogenating the first powder to convert at least part of the first powder into metal hydrides; (c) mixing the first hydrogenated powder with a second powder of an additive, the proportion by mass of the second powder in the resulting mixture ranging from between 1 and 20% by mass; wherein the additive is obtained from a metal alloy of body-centered crystal structure, on titanium, vanadium and at least one another metal M selected from chromium or manganese; and (d) milling the mixture of the first and second powders, in which the additive is obtained by co-fusion followed by a cooling or by mechanosynthesis by co-milling, of the following metal mixture: a metal mixture, which is: - a first metal alloy, of body-centered crystal structure, based on titanium (Ti), on vanadium, and on another metal M selected from among chromium (Cr), manganese (Mn), and alloys of these metals; or - a mixture of the metals forming said metal alloy, in the proportions of said first metal alloy, these metals being present in the mixture as simple metals and/or as metal alloys; and a mixture which is - a second metal alloy comprising: from 38 to 42 mol % of a first metal selected from among zirconium (Zr), niobium (Nb), molybdenum (Mo), hafnium (Hf), tantalum (Ta), tungsten, and mixtures of these metals; from 56 to 60 mol % of a second metal selected from among nickel (Ni), copper (Cu), and alloys of these metals, or - or a mixture of the metals forming said second metal alloy, in the proportions of said second metal alloy, these metals being present in the mixture as simple metals or as metal alloys; with a mass ratio /(m1+m2) ranging from 0.1% to 20% by mass in the co-fusion step. (a) providing a first powder of a magnesium-based material; (b) hydrogenating the first powder to convert at least part of the first powder into metal hydrides; (c) mixing the first hydrogenated powder with a second powder of an additive, the proportion by mass of the second powder in the resulting mixture ranging from between 1 and 20% by mass; wherein the additive is obtained from a metal alloy of body-centered crystal structure, on titanium, vanadium and at least one another metal M selected from chromium or manganese; and (d) milling the mixture of the first and second powders, in which the additive is obtained by co-fusion followed by a cooling or by mechanosynthesis by co-milling, of the following metal mixture: a metal mixture, which is: - a first metal alloy, of body-centered crystal structure, based on titanium (Ti), on vanadium, and on another metal M selected from among chromium (Cr), manganese (Mn), and alloys of these metals; or - a mixture of the metals forming said metal alloy, in the proportions of said first metal alloy, these metals being present in the mixture as simple metals and/or as metal alloys; and a mixture which is - a second metal alloy comprising: from 38 to 42 mol % of a first metal selected from among zirconium (Zr), niobium (Nb), molybdenum (Mo), hafnium (Hf), tantalum (Ta), tungsten, and mixtures of these metals; from 56 to 60 mol % of a second metal selected from among nickel (Ni), copper (Cu), and alloys of these metals, or - or a mixture of the metals forming said second metal alloy, in the proportions of said second metal alloy, these metals being present in the mixture as simple metals or as metal alloys; a metal mixture, which is: - a first metal alloy, of body-centered crystal structure, based on titanium (Ti), on vanadium, and on another metal M selected from among chromium (Cr), manganese (Mn), and alloys of these metals; or - a mixture of the metals forming said metal alloy, in the proportions of said first metal alloy, these metals being present in the mixture as simple metals and/or as metal alloys; and - a first metal alloy, of body-centered crystal structure, based on titanium (Ti), on vanadium, and on another metal M selected from among chromium (Cr), manganese (Mn), and alloys of these metals; or - a mixture of the metals forming said metal alloy, in the proportions of said first metal alloy, these metals being present in the mixture as simple metals and/or as metal alloys; and a mixture which is - a second metal alloy comprising: from 38 to 42 mol % of a first metal selected from among zirconium (Zr), niobium (Nb), molybdenum (Mo), hafnium (Hf), tantalum (Ta), tungsten, and mixtures of these metals; from 56 to 60 mol % of a second metal selected from among nickel (Ni), copper (Cu), and alloys of these metals, or - or a mixture of the metals forming said second metal alloy, in the proportions of said second metal alloy, these metals being present in the mixture as simple metals or as metal alloys; - a second metal alloy comprising: from 38 to 42 mol % of a first metal selected from among zirconium (Zr), niobium (Nb), molybdenum (Mo), hafnium (Hf), tantalum (Ta), tungsten, and mixtures of these metals; from 56 to 60 mol % of a second metal selected from among nickel (Ni), copper (Cu), and alloys of these metals, or from 38 to 42 mol % of a first metal selected from among zirconium (Zr), niobium (Nb), molybdenum (Mo), hafnium (Hf), tantalum (Ta), tungsten, and mixtures of these metals; from 56 to 60 mol % of a second metal selected from among nickel (Ni), copper (Cu), and alloys of these metals, or - or a mixture of the metals forming said second metal alloy, in the proportions of said second metal alloy, these metals being present in the mixture as simple metals or as metal alloys;