A 2LiBH(4)-MgH2-MoS2 composite was prepared by solid-state ball milling, and the effects of MoS2 as an additive on the hydrogen storage properties of 2LiBH(4)-MgH2 system together with the corresponding mechanism were investigated. As shown in the TG-DSC and MS results, with the addition of 20 wt.% of MoS2, the onset dehydrogenation temperature is reduced to 206 degrees C, which is 113 degrees C lower than that of the pristine 2LiBH(4)-MgH2 system. Meanwhile, the total dehydrogenation amount can be increased from 9.26 wt.% to 10.47 wt.%, and no gas impurities such as B2H6 and H2S are released. Furthermore, MoS2 improves the dehydrogenation kinetics, and lowers the activation energy (E-a) 34.49 kJ mol(-1) of the dehydrogenation reaction between Mg and LiBH4 to a value lower than that of the pristine 2LiBH(4)-MgH2 sample. According to the XRD test, Li2S and MoB2 are formed by the reaction between LiBH4 and MoS2, which act as catalysts and are responsible for the improved hydrogen storage properties of the 2LiBH(4)-MgH2 system. Copyright (C) 2013, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.