Metal hydride applications span a wide variety of tech! nologies\ e[g[\ energy conversion\ chemical compressors and hydrogen storage[ A knowledge of heat and mass transfer in a metal hydride reactor during the absorption and desorption of hydrogen is important for performance optimization of the reactor[ One of the key requirements in the design of metal hydride bed is the enhancement of the e}...

The hydridic character of octahedral metal hydride complexes of groups VI, VII and VIII has been systematically studied using molecular electrostatic potential (MESP) topography. The absolute minimum of MESP at the hydride ligand (Vmin) and the MESP value at the hydride nucleus (VH) are found to be very good measures of the hydridic character of the hydride ligand. The increasing/decreasing ele...

In this review article, the fundamentals of electrochemical reactions involving metal hydrides are explained, followed by a report of recent progress in hydrogen storage alloys for electrochemical applications. The status of various alloy systems, including AB₅, AB₂, A₂B₇-type, Ti-Ni-based, Mg-Ni-based, BCC, and Zr-Ni-based metal hydride alloys, for their most important electrochemical applicat...

Although its value varies with the microstructure, hysteresis always accompanies hydride formation and decomposition in Pd(pure)-H, e.g., it is present even in nano-crystalline and thin films. Internal oxidation of Pd0.93Cr0.07 alloys leads to a pure Pd matrix containing nano-crystalline chromia precipitates. The characteristic hysteresis of Pd-H almost disappears in this form of Pd. The reason...

High-pressure metal hydride vehicular hydrogen storage systems can offer good overall gravimetric and volumetric hydrogen densities. Enhanced heat transfer techniques will be essential to achieve established goals for tank filling times. A numerical model is developed to simulate the hydrogen filling process of a subscale high-pressure metal hydride (Ti1.1CrMn) system. The model is validated by...

Novel inorganic alkali and alkaline earth hydrides of the f o r m u l a MH *, MH 2 * , and MH X * wherein M is the metal, X , is a halide, and H * comprises a novel high binding energy hydride ion were synthesized in a high temperature gas cell by reaction of atomic hydrogen with a catalyst and MH , MH 2 , or MX corresponding to an alkali metal or alkaline e a r t h metal compound, respectively...

KOH-based electrolytes with different salt additives were investigated to reduce their corrosive nature toward Mg/Ni metal hydride alloys used as negative electrodes in nickel metal hydride (Ni/MH) batteries. Alkaline metal halide salts and oxyacid salts were studied as additives to the traditional KOH electrolyte with concentrations varying from 0.005 M to 1.77 M. Effects of the cations and an...

Reversible, heterolytic addition of H2 across an iron-boron bond in a ferraboratrane with formal hydride transfer to the boron gives iron-borohydrido-hydride complexes. These compounds catalyze the hydrogenation of alkenes and alkynes to the respective alkanes. Notably, the boron is capable of acting as a shuttle for hydride transfer to substrates. The results are interesting in the context of ...

Directed Energy Weapon (DEW) systems in a pulse operation mode dissipate excessively large, transient waste heat because of their inherent inefficiencies. The heat storage system can store such a pulsed heat load not relying on oversized systems and dissipate the stored heat over time after the pulse operation. A compressor-driven metal hydride heat storage system was developed for efficient, c...

We present ab initio calculations (generalized valence bond plus configuration interaction, using relativistic effective core potentials) on the monopositive diatomic metal hydride ions of the third transition-metal series ( H M + through HgH+ plus BaH+ and LaH+). We analyze the trends in bond energies, equilibrium geometries, bond character, and excitation energies in terms of ( 1 ) the atomic...