Solubility of metal-boron-hydrogen compounds.

Boron-hydrogen compounds are of increasing importance as electrolytes in solid state batteries, for hydrogen storage and possibly as high temperature super conductors. Solvent based methods are of increasing importance to obtain pure products, for purification of materials and also for the synthesis of novel compounds. In this context, the solubility information of several classes of metal-boron-hydrogen compounds such as borohydrides, -decahydridodecaborates, -dodecahydridododecaborates, - and -hydridoborates in typical solvents is vital.

Optimising thermochemical energy storage: a comprehensive analysis of CaCO composites with CaSiO, CaTiO, and CaZrO.

With the increasing amount of renewable energy produced, many governments and industries are pushing for the installation of battery energy storage system (BESS) solutions. Thermal batteries are systems that store heat made from various energy sources, and can be used to produce electricity upon demand. These systems are easily scalable and can be installed in cities, homes and remote locations.

Producing Alkali Metal Hydrides from Hydroxides.

In this study, a novel method for producing different alkali metal hydrides (NaH, KH, RbH, and CsH) from their corresponding metal hydroxides (NaOH, KOH, RbOH, and CsOH) is presented. For the production of NaH from NaOH, a variety of metallic reducing agents (Mg, Al, Si, CaH, Cr, Mn, and Sr) were investigated. The reactions took place in an autoclave reactor with paraffin oil at 250 °C and 14 bar of H pressure.

Establishing ZIF-8 as a reference material for hydrogen cryoadsorption: An interlaboratory study.

Hydrogen storage by cryoadsorption on porous materials has the advantages of low material cost, safety, fast kinetics, and high cyclic stability. The further development of this technology requires reliable data on the H uptake of the adsorbents, however, even for activated carbons the values between different laboratories show sometimes large discrepancies. So far no reference material for hydrogen cryoadsorption is available.

Stannaborates: tuning the ion conductivity of dodecaborate salts with tin substitution.

Metal substituted dodecaborate anions can be coupled with alkali metal cations to have great potential as solid-state ion conductors for battery applications. A tin atom can replace a B-H unit within an unsubstituted dodecaborate cage to produce a stable, polar divalent anion. The chemical and structural change in forming a stannaborate results in a modified crystal structure of respective group 1 metal salts, and as a result, improves the material's ion conductivity.

Thermochemical energy storage in barium carbonate enhanced by iron(III) oxide.

Renewable energy requires cost effective and reliable storage to compete with fossil fuels. This study introduces a new reactive carbonate composite (RCC) where FeO is used to thermodynamically destabilise BaCO and reduce its decomposition temperature from 1400 °C to 850 °C, which is more suitable for thermal energy storage applications. FeO is consumed on heating to form BaFeO, which is a stable Fe source for promoting reversible CO reactions.

NaBH and Na(BH)(BH) as potential solid-state electrolytes for Na-ion batteries.

Solid-state sodium batteries have attracted great attention owing to their improved safety, high energy density, large abundance and low cost of sodium compared to the current Li-ion batteries. Sodium-boranes have been studied as potential solid-state electrolytes and the search for new materials is necessary for future battery applications. Here, a facile and cost-effective solution-based synthesis of NaBH and Na(BH)(BH) is demonstrated.

Thermochemical energy storage performance of zinc destabilized calcium hydride at high-temperatures.

CaH2 has 20 times the energy density of molten salts and was patented in 2010 as a potential solar thermal energy storage material. Unfortunately, its high operating temperature (>1000 °C) and corrosivity at that temperature make it challenging to use as a thermal energy storage (TES) material in concentrating solar power (CSP) plants. To overcome these practical limitations, here we propose the thermodynamic destabilization of CaH2 with Zn metal.

Thermal properties of thermochemical heat storage materials.

The thermal conductivity, thermal diffusivity and heat capacity of materials are all vital properties in the determination of the efficiency of a thermal system. However, the thermal transport properties of heat storage materials are not consistent across previous studies, and are strongly dependent on the sample composition and measurement method. A comprehensive analysis of thermal transport properties using a consistent preparation and measurement method is lacking.

Thermodynamics and performance of the Mg-H-F system for thermochemical energy storage applications.

Magnesium hydride (MgH) is a hydrogen storage material that operates at temperatures above 300 °C. Unfortunately, magnesium sintering occurs above 420 °C, inhibiting its application as a thermal energy storage material. In this study, the substitution of fluorine for hydrogen in MgH to form a range of Mg(HF) (x = 1, 0.

The influence of LiH on the rehydrogenation behavior of halide free rare earth (RE) borohydrides (RE = Pr, Er).

Rare earth (RE) metal borohydrides are receiving immense consideration as possible hydrogen storage materials and solid-state Li-ion conductors. In this study, halide free Er(BH4)3 and Pr(BH4)3 have been successfully synthesized for the first time by the combination of mechanochemical milling and/or wet chemistry. Rietveld refinement of Er(BH4)3 confirmed the formation of two different Er(BH4)3 polymorphs: α-Er(BH4)3 with space group Pa3[combining macron], a = 10.

Complex transition metal hydrides incorporating ionic hydrogen: thermal decomposition pathway of Na2Mg2FeH8 and Na2Mg2RuH8.

Complex transition metal hydrides have potential technological application as hydrogen storage materials, smart windows and sensors. Recent exploration of these materials has revealed that the incorporation of anionic hydrogen into these systems expands the potential number of viable complexes, while varying the countercation allows for optimisation of their thermodynamic stability. In this study, the optimised synthesis of Na2Mg2TH8 (T = Fe, Ru) has been achieved and their thermal decomposition properties studied by ex situ Powder X-ray Diffraction, Gas Chromatography and Pressure-Composition Isotherm measurements.

In situ high pressure NMR study of the direct synthesis of NaAlH4.

The direct synthesis of NaAlH4 has been studied, for the first time, by in situ (27)Al and (23)Na wide-line NMR spectroscopy using high pressure NMR apparatus. Na3AlH6 formation is observed within two minutes of hydrogen addition, while NaAlH4 is detected after a total of four minutes. This indicates the formation of the hexahydride does not proceed to completion before the formation of the tetrahydride ensues.

Lewis base complexes of AlH3: prediction of preferred structure and stoichiometry.

The structures adopted by a range of complexes AlH3·nL, (n = 1 or 2), have been explored in detail to identify the factors that determine the value of n, and whether a monomeric or dimeric arrangement is preferred for the 1 : 1 complexes. Single-crystal X-ray diffraction, vibrational and NMR spectroscopies, and thermal analysis data have been collected, DFT calculations have been performed for AlH3·nL species, and pK(a) values have been collated for a series of amine and phosphine ligands L. The pK(a) of the ligand L exerts an important influence on the type of complex formed: as the basicity of L increases, a monomeric structure is favoured over a dimeric arrangement.

Lewis base complexes of AlH3: structural determination of monomeric and polymeric adducts by X-ray crystallography and DFT calculations.

The AlH3 adducts of TMEDA (Me2NCH2CH2NMe2), DIOX (O(CH2CH2)2O), TEA (Et3N), BDMA (PhNMe2), and TMPDA (Me2NCH2CH2CH2NMe2) have each been characterised by single-crystal X-ray diffraction at low temperature, by (1)H, (14)N and (27)Al NMR and FT-Raman and FT-IR spectroscopy, and by DFT calculations and elemental analysis. Hence, AlH3·TMEDA and AlH3·DIOX are both shown to adopt a polymeric structure, with the bidentate ligand bridging two Al centres, each of which adopts a trigonal bipyramidal (TBP) arrangement with equatorial hydride moieties. The 1 : 2 adduct AlH3·2BDMA is monomeric but the geometry at the Al centre resembles closely that of the polymeric TMEDA and DIOX complexes.

Induced fit interanion discrimination by binding-induced excimer formation.

The synthesis, photophysical, and anion-binding properties of a series of di-, tri-, and tetrapodal anion-binding hosts based on aminopyridinium units with pyrenyl reporter groups are described. The ditopic mesitylene-derived calix[4]arene-based host 4 binds strongly to dicarboxylates, particularly malonate, in a 2:1 anion:host ratio but is essentially nonemissive in the presence of all anions except chloride because of intramolecular quenching by the pyridinium units. Addition of chloride results in a conformational change, giving an initial increase in emission assigned to intramolecular excimer formation.

Modular assembly of a preorganised, ditopic receptor for dicarboxylates.

Two types of calix[4]arene derived hosts for anions with, respectively, 1,3-alternate and cone conformations have been prepared; the 1,3-alternate system binds dicarboxylate anions in a ditopic manner while the cone compounds are deprotonated by carboxylates.