Hydrogen Sorption in Li12C60

The lithium-intercalated fulleride Li12C60 was investigated in view of a lightweight hydrogen storage material due to the low molecular weight of its constituents. Deuterium (D-2) absorption in Li12C60 shows an uptake of up to 9.5 mass % D-2 (equivalent to similar to 5 mass % H-2 for the same stoichiometry). Under a pressure of 190 bar the onset of absorption was observed at a temperature below 100 degrees C, which is 200 degrees C lower than that for pure C-60. Deuterium desorption was investigated by in-situ neutron powder diffraction, and at a pressure of 1 bar desorption was observed above 300 degrees C. The ab/desorption is accompanied by a partial de/reintercalation of lithium, observed by the appearance and disappearance of LiD reflections after absorption and during desorption, respectively. A minor part of deuterium is present in ionic form in LiD, and the major part is covalently bound in a Li-depleted compound Li12-xC60D36+y.