The decomposition pathway of the complex hydride Al3Li 4(BH4)13 is in the focus of this study. Initially the compound attracted great interest due to its high H2 capacity (17.2 wt.%) and desorption at moderate temperatures (<100 °C). This work sheds light on its decomposition reaction by a unique experimental setup of thermogravimetry combined with spectroscopic gas phase analysis (FT-IR and MS) at ambient conditions. It is observed that the compound itself is metastable and decomposes immediately into its components, solid LiBH 4 and Al(BH4)3 which is monitored in the gas phase. Carbon addition decreases the observed mass loss and the spectroscopic gas phase analysis is used to learn about the impact of carbon addition. Copyright © 2012, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.