The most favorable dopants for 1 solid-state hydrogen-storage materials are still considered to be compounds of titanium in spite of intensive research on other catalysts. Here, we show that NaAlH4 doped with SCCl3 is a highly efficient dopant, both with respect to storage capacity and kinetics: 2 mol % ScCl3 exhibits a nearly theoretical hydrogen-storage capacity (4.9 wt %, see graph). Other rare-earth metal trichlorides are also investigated.