Here we propose the investigation of intermediate compounds obtained during the decomposition of the multicomponent hydrogen storage system 2 LiBH4 : MgH2 using ex-situ inelastic neutron scattering (INS) technique. Ab-initio calculations combined with experimental data suggested different reaction paths via the formation of phases such as Li2B12H12 or LiBH. Prior to the experiment, we plan to isolate the intermediate phases by quenching the decomposing 2:1 mixtures at the relevant temperatures. The aim of the current proposal is to identify the chemical environment of each proton present by evaluating their total mean kinetic energy within the (Q,w) trajectories covered on TOSCA.