The dispersion of metal-element containing additives with hydrogen storage particles of the family of hydrogen-rich materials, M'.sub.xM''.sub.yN.sub.zH.sub.d as specified herein, markedly lowers the temperature at which hydrogen is removed from the particles. For example, the dispersion of additives containing one or more of iron, nickel, palladium, or platinum with particles of Li.sub.50B.sub.17N.sub.33H.sub.133 provides a composition from which hydrogen is readily removed by heating. Use of these metals as their chloride salts makes particularly effective hydrogen release additives.