The significantly enhanced dehydrogenation performance of binary complex system, NH3BH3/LiBH4 center dot NH3, were achieved through a chemical modification of LiH to form ternary composites of x (LiH-NH3BH3)/LiBH4 center dot NH3. Among the studied composites, 3LiH-3NH(3)BH(3)/LiBH4 center dot NH3 released ca. 10 wt. % high-pure hydrogen (>99.9 mol%) below 100 degrees C with fast kinetics, while less than 8 wt. % hydrogen, accompanied with a fair number of volatile byproducts, were released from 3NH(3)BH(3)/LiBH4 center dot NH3 at the same conditions. Further investigations revealed that the hydrogen emission from x (LiH-NH3BH3)/LiBH4 center dot NH3 composites is based on the combination mechanism of Ha(delta+) and H delta- through the interaction between LiH-NH3BH3 and NH3 group in LiBH4 center dot NH3, in which the controllable protic hydrogen source from the stabilized NH3 group played a crucial role in providing optimal stoichiometric ratio of H delta+ and H delta-, and thus leading to the significant improvement of dehydrogenation capacity and purity. Copyright (c) 2012, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.