Materials for hydrogen-based energy storage – past, recent progress and future outlook

Hydrogen is recognized as a possible future energy carrier, which can be produced from renewable energy and water. A major challenge in a future ‘hydrogen economy’ is the development of safe, compact, robust, and efficient means of hydrogen storage, in particular for mobile applications. The present review focuses on light metal boron based hydrides, for which the general interest has expanded significantly during the past few years. Synthesis methods, physical, chemical and structural properties of novel boron based hydrides are reviewed along with new approaches for improving kinetic and thermodynamic properties: (i) anion substitution, (ii) reactive hydride composites and (iii) nanoconfinement of hydrides and chemical reactions. The light metal borohydrides reveal a fascinating structural chemistry and have the potential for storing large amounts of hydrogen. A combination of the different approaches may provide a new route to a wide range of interesting energy storage materials in the future.

Tailoring properties of borohydrides for hydrogen storage: A review

The development of alternative methods for thermal energy storage is important for improving the efficiency and decreasing the cost for Concentrating Solar-thermal 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 oC. 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.

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Metal hydrides for concentrating solar thermal power energy storage

Evaluation of ZrCo and other getters for Tritium handling and storage

The interaction with hydrogen gas of sixteen intermetallics containing zirconium or hafnium at a concentration of at least 50 at.% was studied. It was found that reversible hydrogen absorption involving the formation of a ternary hydride occurred for all the hafnium compounds and for the zirconium compounds of 50 at.% Zr composition. For all compounds of higher zirconium content hydrogen absorption was found to be irreversible because of the formation of the binary hydride ZrH2. Lattice parameters are given for the intermetallic compounds of hafnium before and after charging with hydrogen gas.

Hydrogen absorption in various zirconium- and hafnium-based intermetallic compounds

The interaction of the intermetallic compound ZrNi with hydrogen was studied, and pressure --composition isotherms were obtained at 100, 200, and 250 deg . There was no resemblance to the zirconium--hydrogen system. The alloy formed a definite hydride at a limiting composition ZrNiH/sub 3/, and possibly a second hydride at ZrNiH. X-ray and density measurements on both the alloy and the hydrides indicated a distorted cubic structure for all phases. Hysteresis was observed on the isotherms and a possible explanation for this phenomenon is given on the assumption of lattice defects. (auth)

The System Zirconium–Nickel and Hydrogen

Gadolinium-hydrogen system at elevated temperatures. Vacancy interactions in gadolinium dihydride

The distribution of a gas dissolved in a metal under a thermal gradient and constant pressure is considered An expression for the concentration gradient is derived The effect of compound formation on the distribution and on the shape of pressure--composition isotherms is discussed (auth)

George G. Libowitz

Papers

The System Zirconium–Nickel and Hydrogen

Gadolinium-hydrogen system at elevated temperatures. Vacancy interactions in gadolinium dihydride

Effect of Thermal Gradients on Metal-Gas Systems