Library Item
Synthesis and Characterization of a Lithium-Doped Fullerane for Reversible Hydrogen Storage
Description:
Herein, we present a lithium-doped fullerane (Lix-C60-Hy) that is capable of reversibly storing hydrogen through chemisorption at elevated temperatures and pressures. This system is unique in that hydrogen is closely associated with lithium and carbon upon rehydrogenation of the material and that the weight percent of H2 stored in the material is intimately linked to the stoichiometric ratio of Li:C60 in the material. Characterization of the material (IR, Raman, UV vis, XRD, LDI-TOF-MS, and NMR) indicates that a lithiumdoped fullerane is formed upon rehydrogenation in which the active hydrogen storage material is similar to a hydrogenated fullerene. Under optimized conditions, a lithium-doped fullerane with a Li:C60 mole ratio of 6:1 can reversibly desorb up to 5 wt % H2 with an onset temperature of ?270 °C, which is significantly less than the desorption temperature of hydrogenated fullerenes (C60Hx) and pure lithium hydride (decomposition temperature 500 600 and 670 °C respectively). However, our Lix-C60-Hy system does not suffer from the same drawbacks as typical hydrogenated fullerenes (high desorption T and release of hydrocarbons) because the fullerene cage remains mostly intact and is only slightly modified during multiple hydrogen desorption/absorption cycles. We also observed a reversible phase transition of C60 in the material from face-centered cubic to body-centered cubic at high levels of hydrogenation.
