The decomposition of Na 2 LiAlH 6 is studied by in-situ synchrotron diffraction. By addition of TiF 3 and dehydrogenation-rehydrogenation cycling of the samples new decomposition paths are found. Na 3 AlH 6 is formed on decomposition in the presence of TiF 3 . The additive brings the system closer to equilibrium, and decomposition through Na 3 AlH 6 is demonstrated for the first time. The results are in agreement with previously published computational data. For a cycled sample with 10 mol% TiF 3 Na 2 LiAlH 6 decomposes fully into Na 3 AlH 6 before further decomposition to NaH and Al. This shows clear changes in the kinetics of the system, and may open possibilities of tailoring the decomposition path by the use of additives.