Herein, we present a lithium-doped fullerane (Li(x)-C(60)-H(y)) 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 H(2) stored in the material is intimately linked to the stoichiometric ratio of Li:C(60) in the material. Characterization of the material (IR, Raman, UV-vis, XRD, LDI-TOF-MS, and NMR) indicates that a lithium-doped 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:C(60) mole ratio of 6:1 can reversibly desorb up to 5 wt % H(2) with an onset temperature of ~270 °C, which is significantly less than the desorption temperature of hydrogenated fullerenes (C(60)H(x)) and pure lithium hydride (decomposition temperature 500-600 and 670 °C respectively). However, our Li(x)-C(60)-H(y) 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 C(60) in the material from face-centered cubic to body-centered cubic at high levels of hydrogenation.

The development of alternative methods for thermal energy storage is important for improving the efficiency and decreasing the cost for Concentrating Solarthermal Power (CSP). We focus on the underlying technology that allows metal hydrides to function as Thermal Energy Storage (TES) systems and highlight the current state-of-the-art materials that can operate at temperatures as low as room-temperature and as high as 1100 o C. The potential of metal hydrides for thermal storage is explored while current knowledge gaps about hydride properties, such as hydride thermodynamics, intrinsic kinetics and cyclic stability, are identified. The engineering challenges associated with utilising metal hydrides for high-temperature thermal energy storage are also addressed.

Our investigation of the chemical and physical properties of the alkali-metal dodecahydro-closo-dodecaborate, Li2B12H12, determined that it is a bi-functional material that can be used as a solid state electrolyte in lithium ion batteries and as a luminescent down conversion dye in scalable transparent displays. A series of electrochemical measurements of morphologically altered samples, via mechanical milling, was conducted. The measurements indicated that mechanical alternations of the Li2B12H12 morphology makes it an excellent lithium ion conductor in the solid state with excepetional ionic conductivity at room temperature (0.31 mS/cm) and is compatible with a metallic lithium electrode up to 6.0V. In addition, all solid state half and full electrochemical cells were assembled and successfully cycled using Li2B12H12 as a solid state electrolyte at temperatures as low as 30°C with good capacity retention. The photophysical properties of Li2B12H12 were also investigated. Li2B12H12 has an emission maximum of ~460 nm in a variety of solvents with Stokes' shifts up to 175 nm observed. Li2B12H12 was incorporated in a polyvinyl alcohol (PVA) thin film to demonstrate its application as a luminescent down-conversion dye in a transparent head-up display when excited by a UV projection source.

Hydrogen storage, fullerene, LiBH 4 , nanocomposite, fullerane Reversible hydrogen storage in a LiBH 4 :C 60 nanocomposite (70:30 wt. %) synthesized by solvent-assisted mixing has been demonstrated. D uring the solvent-assisted mixing and nanocomposite formation, a chemical reaction occurs in which the C 60 cages are significantly modified by polymerization as well as by hydrogenation (fullerane formation) in the presence of LiBH 4 . We have determined that two distinct hydrogen desorption events are observed upon rehydrogenation of the material, which are attributed to the reversible formation of a fullerane (C 60 H x ) as well as a LiBH 4 species. This system is unique in that the carbon species (C 60 ) actively participates in the hydrogen storage process which differs from the common practice of 2 melt infiltration of high surface area carbon materials with LiBH 4 (nanoconfinment effect). This nanocomposite demonstrated good reversible hydrogen storage properties as well as the ability to absorb hydrogen under mild conditions (pressures as low as 10 bar H 2 or temperatures as low as 150°C). The nanocomposite was characterized by TGA-RGA, DSC, XRD, LDI-TOF-MS, FT-IR, 1 H NMR, and APPI MS.

Thermal energy storage systems based on metal hydride pairs using high efficiency materials are evaluated. The low temperature metal hydrides NaAlH 4 and Na 3 AlH 6 were cycled to determine stability of hydrogen capacity over extended cycling. Addition of aluminum and expanded natural graphite were found to enhance the cycling stability of NaAlH 4 . Potential high temperature metal hydrides were investigated based on NaMg materials. A techno-economic analysis was performed to evaluate the performance a thermal energy storage system based on two metal hydride pairs: NaMgH 3 :NaAlH 4 and NaMgH 2 F:Na 3 AlH 6 . The resulting analysis suggests that the two systems have the potential to reach low cost and high efficiency performance targets.