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Lithium hydride (LiH) has attracted attention because of its high density hydrogen storage energy. However, the poor dehydrogenation properties cannot be used as an effective hydrogen storage material. In this paper, we apply the first-principles calculations to study the influence of noble metals on the electronic and optical properties of LiH hydride. Here, five noble metals TM(TM = Ag, Au, Pd, Pt and Ru) are considered. The calculated result shows that the noble metals are thermodynamic stability in LiH hydride. In particular, it is found that only the Pt-doped LiH is a dynamical stability compared to the other noble metals doping. Here, the calculated band gap of the pure LiH is 3.002 eV. Interestingly, these noble metals are beneficial to improve the electronic transfer (near Fermi level) of LiH because the introduction of noble metal induces the H-1s state to the Fermi level, making the band gap of the noble metal doped LiH disappear. In addition, we study the influence of noble metal Pt on the optical properties of LiH. It is found that the Pt doping can enhance the optical activity of LiH for visible light and infrared light, presumably caused by the addition of d state.

The paper deals with the calculation of electron interaction potentials with the main charged [110] axes in a lithium hydride crystal at T = 300, 600, and 900 K temperatures. For relativistic electrons with Lorentz factors γ = 50, 75, 100 the energy and corresponding wave functions of transverse levels of channeling motion are found numerically. The radiation spectra of channeling electrons with (and without) accounting an angular dispersion are calculated on the basis of these data.

Discovering the underlying reason for Li anode failure is a critical step towards applications of lithium metal batteries (LMBs). In this work, we conduct deuterium-oxide (D2 O) titration experiments in a novel on-line gas analysis mass spectrometry (MS) system, to determine the content of metallic Li and lithium hydride (LiH) in cycled Li anodes disassembled from practical LiCoO2 /Li LMBs. The practical cell is comprised of ultrathin Li anode (50 μm), high loading LiCoO2 (17 mg cm-2 , 2.805 mAh cm-2 ) and different formulated electrolytes. Our results suggest that the amount of LiH accumulation is negatively correlated with cyclability of practical LMBs. More importantly, we reveal a temperature sensitive equilibrium (Li + 1/2 H2 ⇌ LiH) governing formation and decomposition process of LiH at Li anode. We believe that the unusual understanding provided by this study will draw forth more insightful efforts to realize efficient Li protection and the ultimate applications of "holy grail" LMBs.

In this paper, the optical properties of Lithium hydride (LiH), in rocksalt structure, with space group, Fm3m, in cubic (FCC) system, have been discussed. The theoretical background of the relation between the dielectric function, and, other optical constants has been examined. The real and imaginary parts of the dielectric function have also been scrutinized. The consequences of the exchange correlation potentials (GGA and GGA + U) applied to the absorption peaks and edges of the compound have also been spoken of. It was observed, at the application of GGA + U and GGA to the first absorption edge matched together; but there was overt difference in fine structure at higher energies due to the presence of the former exchange correlation approximation.

The results of precision experiments concerning neutron passage through the layers of lithium-7 hydride are reported. Activation integrals for neutron activation detectors positioned at various points of the composite lithium-7 hydride reflector mounted at the end of the uranium breeder system have been determined. Spectral indices have been calculated on the basis of the data obtained.

The study focuses on hydrogen desorption characteristics of lithium hydride (LiH), sodium hydride (NaH), calcium hydride (CaH2), and titanium hydride (TiH2) which permits a possible path regarding challenging goals of US DOE standards. This research reported the consequences of enrichment in hydrogen uptake 7.02 wt% in lithium hydride, 7.71 wt% in sodium hydride, 5.91 wt% in calcium hydride, and 5.00 wt% in titanium hydride using silicon as an additive when evaluated with the help of volumetric technique. The ball milling process with silicon additive for LiH, NaH, CaH2, and TiH2 shows depletion in dehydrogenation temperatures 523 K, 453 K, 488 K, and 463 K respectively. Similarly, the reduction in the activation energies reported due to ball milling process with silicon additive are 37 kJ/mol for lithium hydride, 42 kJ/mol for sodium hydride, 56 kJ/mol for calcium hydride and 45 kJ/mol for titanium hydride compared with crystalline powder samples of the respective materials. The outcome of Fourier-transform infrared spectroscopy of milled hydride samples after decomposition intimate rapid decrease in transmittance intensities due to hydrogen release because of the destabilization effect caused by silicon additive. The porosity and sponginess in high-resolution Transmission electron microscopy images after dehydrogenation reveals the hydrogen desorption from the sample materials.

Lithium coatings in the Lithium Tokamak eXperiment (LTX) led to flat temperature profiles. The flat temperature profiles were observed along with a hot, low density edge, implying a broad, collisionless scrape-off layer (SOL). Additionally, in vacuo X-ray photoelectron spectroscopy (XPS) measurements established that lithium coatings evaporatively deposited onto high-Z plasma facing components (PFCs) became oxidized while retaining the ability to achieve good plasma performance long after lithium was applied to the PFCs. Longstanding theory predicted flat temperature profiles with low recycling walls, which was presumed to be due to hydrogen binding with elemental lithium to form lithium hydride. The presence of oxidized lithium, however, raised questions regarding the exact mechanism of hydrogen retention in LTX. To investigate these questions, the upgraded facility LTX- $\beta $ includes a new sample exposure probe (SEP) for more detailed in vacuo analysis of PFC samples. The SEP is equipped with a vacuum suitcase capable of transporting samples representative of the LTX- $\beta $ outer midplane PFCs to a stand-alone XPS system while maintaining pressures lower than the LTX- $\beta $ base vacuum to limit the contamination between sample exposure and analysis. The low-energy resolution XPS system used in past experiments could only enable the determination of elemental percentages on the PFC sample surfaces. Because the new XPS system has higher energy resolution, it is more direct to assign chemical compounds to the measured binding energies. This capability has been confirmed by comparing XPS data from PFC test samples with measurements using a commercial high-resolution XPS system. Quartz crystal microbalances (QCMs) were used to quantify the thickness of the deposited lithium on the LTX- $\beta $ PFCs. This article describes the application of the SEP to characterize the PFC surfaces using XPS and their relationship to plasma conditions.

Hydrogen as a clean and abundant energy source with high energy density is considered as a promising solution to future energy crisis, although storage of hydrogen is still challenging. Lithium hydride can be an alternative for hydrogen storage because of its small volume and high storage capacities, although this material is unsuitable as hydrogen reservoir because of its high dehydriding temperature. The density functional theory calculations based on the first principle are applied to study the physical properties of LiH without and with different metal M (M=Al, Fe, and Ru). The M-substituted systems exhibit lower dehydriding temperatures than the pure LiH, and Li1−x Al x H may be the most suitable candidate for hydrogen reservoir owing to the high hydrogen content and low dehydriding temperature. The stability and thermodynamic properties for hydrogen storage are discussed for these systems. The kinetics and the optical activity in the visible and infrared regions are enhanced by the metal dopants, characterized by the M impurity bands in the band gaps of the doped systems.

A novel alloy LaTi2Ni5Al4 is investigated in this work. This quaternary composite belongs to the new generation of AB3 intermetallics elaborated using the mechano-milling method. Several analytical techniques are operated in order to verify and confirm the crystallographic patterns following the growth progression of this nanoalloy. Starting from elemental metals, the authors show that they have basically LaTi2Ni5Al4 major pattern corresponding to the symmetry crystal system (Trigonal R-3 m SG: 166). Structure refinement simulation demonstrates that performing this preparation with a laboratory grinding and milling benchtop, they obtain a maximum proportion of AB3 intermetallic alloy after 20 h of metallurgy work processing. The proposition of useful stabilised solid-hydrogen encapsulation is highlighted and tested using a specific lithium-hydride cell.

In this study, the Klein–Gordon equation was solved with the Deng–Fan potential using the Nikiforov–Uvarov-functional-analysis in higher dimensions. By employing the improved Pekeris-type approximation scheme, the relativistic and nonrelativistic energy spectra of the Deng–Fan potential were obtained in closed form. In addition, the scattering state phase shift expression of Deng–Fan potential was obtained in higher dimensions. The effects of the vibrational and rotational quantum numbers on the vibrational energies and scattering phase shift of hydrogen chloride (HCl) and lithium hydride (LiH) diatomic molecules were studied numerically and graphically at different dimensions. Interestingly, there exists inter-dimensional degeneracy symmetry for the scattering phase shift of the diatomic molecular systems considered. Our results generally were in agreement with that obtained from literatures.

The evolution of defects such as pores at elevated temperatures is crucial for revealing the thermal stability of lithium hydride ceramic. The in situ evolution of pores in sintered lithium hydride ceramic from 25 °C to 500 °C, such as the statistics of pores and the 3D structure of pores, was investigated by X-ray computed tomography. Based on the statistics of pores, the porosity significantly increased from 25 °C to 200 °C and decreased after 200 °C, due to the significant change in the number and total volume of the round-shaped pores and the branched crack-like pores with an increasing temperature. According to the 3D structure of pores, the positions of pores did not change, and the sizes of pores went up in the range of 25–200 °C and went down after 200 °C. Some small round-shaped pores with an Equivalent Diameter of less than 9 μm appeared at 200 °C and disappeared at elevated temperatures. Some adjacent pores of all types connected at 200 °C, and some branched crack-like pores gradually disconnected with an increasing temperature. The expansion of pores at 200 °C caused by the release of residual hydrogen and the contraction of pores after 200 °C because of the migration and diffusion of some hydrogen in pores might be the reason for the evolution of pores with an increasing temperature.

Ion beam analyses were completed on single crystal LiD (lithium hydride with deuterium on the hydrogen sites) to determine products of hydrolysis with decarbonated H2O (with protium-hydrogen) in an inert gas. Rutherford backscattering spectrometry showed movement of oxygen into the bulk of LiD samples. Hydrolysis rates for the single crystal LiD showed relatively slow initial growth of an oxygen-containing layer. Final growth rates varied widely with H2O level, from 1010 to 1015 (atoms/cm2)/min. at 5.6 and 28 mmol/min. H2O respectively. Simulations of spectra show the hydrolysis product to be LiOH. Elastic recoil detection identifies the hydrogen in the hydroxide layer upon dosing with H2O (with natural, protiated hydrogen) as primarily protium. Micrographs showed island growth occurring initially, with convergence to a full-coverage hydrolysis layer.

Lithium-rich superstoichiometric solid solutions MgLixMnO3 – δ were obtained by intercalation into the spinel MgMnO3 – δ using lithium hydride LiH as an intercalating agent through the stage of the formation of mechanocomposites. The accompanying chemical transformations involving the hydride ion were studied. Conventional ceramic synthesis methods and alternative intercalating agents were analyzed. It was shown that hydride intercalation produces pure samples of single-phase spinels with high lithium content (MgLi0.75MnO3), which is three times higher than that reachable by conventional ceramic synthesis methods.

The industry‐scale production of methylchloromonosilanes in the Müller–Rochow Direct Process is accompanied by the formation of a residue, the direct process residue (DPR), comprised of disilanes MenSi2Cl6‐n (n=1–6). Great research efforts have been devoted to the recycling of these disilanes into monosilanes to allow reintroduction into the siloxane production chain. In this work, disilane cleavage by using alkali and alkaline earth metal salts is reported. The reaction with metal hydrides, in particular lithium hydride (LiH), leads to efficient reduction of chlorine containing disilanes but also induces disproportionation into mono‐ and oligosilanes. Alkali and alkaline earth chlorides, formed in the course of the reduction, specifically induce disproportionation of highly chlorinated disilanes, whereas highly methylated disilanes (n>3) remain unreacted. Nearly quantitative DPR conversion into monosilanes was achieved by using concentrated HCl/ether solutions in the presence of lithium chloride., Too valuable for disposal or incineration: Simple recycling of the Müller–Rochow Direct Process residue with LiH yields monosilanes suitable for the reintroduction into the silicone production chain.

Lithiated thin films are necessary for the fabrication of novel solid-state batteries, including the electrodes and solid electrolytes. Physical vapour deposition and chemical vapour deposition can be used to deposit lithiated films. However, the issue of conformality on non-planar substrates with large surface area makes them impractical for nanobatteries the capacity of which scales with surface area. Atomic layer deposition (ALD) avoids these issues and is able to deposit conformal films on 3D substrates. However, ALD is limited in the range of chemical reactions, due to the required volatility of the precursors. Moreover, relatively high temperatures are necessary (above 100 °C), which can be detrimental to electrode layers and substrates, for example to silicon into which the lithium can easily diffuse. In addition, several highly reactive precursors, such as Grignard reagents or n-butyllithium (BuLi) are only usable in solution. In theory, it is possible to use BuLi and water in solution to produce thin films of LiH. This theoretical reaction is self-saturating and, therefore, follows the principles of solution atomic layer deposition (sALD). Therefore, in this work the sALD technique and principles have been employed to experimentally prove the possibility of LiH deposition. The formation of homogeneous air-sensitive thin films, characterized by using ellipsometry, grazing incidence X-ray diffraction (GIXRD), in situ quartz crystal microbalance, and scanning electron microscopy, was observed. Lithium hydride diffraction peaks have been observed in as-deposited films by GIXRD. X-ray photoelectron spectroscopy and Auger spectroscopy analysis show the chemical identity of the decomposing air-sensitive films. Despite the air sensitivity of BuLi and LiH, making many standard measurements difficult, this work establishes the use of sALD to deposit LiH, a material inaccessible to conventional ALD, from precursors and at temperatures not suitable for conventional ALD.

Due to the thermalization of lithium hydride (LiH) in nuclear propulsion particle bed reactor (PBR), thermal-kernel effect of LiH and its impact on the reactivity of PBR was studied. The phonon properties of LiH have been analyzed by the first-principles simulations using the VASP and PHONON codes. Applying the generated phonon density of states, the ACE-format thermal-neutron cross-section library of LiH has been generated by NJOY code. Neutronic modeling and simulation of PBR were done in this paper. The impact of LiH thermalization on the reactivity feedback of PBR was studied and analyzed. From the numerical results, it can be observed that the thermal effect of LiH was positive to the reactivity of PBR. The approximation of the free-gas model introduces significant error over 2000 pcm (10−5). In order to find the thermal mechanism of LiH, detailed research and analysis towards the thermal expansion and thermal dissociation have been also done. It was found that the thermal-kernel effect finally made the most contribution. In order to improve the safety of PBR reactor, the mixed moderator method was designed to reduce or resolve the positive moderator temperature effect.

The crystal structural characteristics of the [NiEn3]MoO4 complex salt (En is ethylenediamine) at 90 K are as follows: space group $$P\overline 3 ,\;a = 15.9307\left( 9 \right)\;\acute{\mathring{\mathrm{A}}} ,\;c = 9.9238\left( 6 \right)\;\acute{\mathring{\mathrm{A}}} ,\;V = 2181.1\left( 3 \right)\;{\acute{\mathring{\mathrm{A}}} ^3},\;Z = 6,\;{d_{\rm{x}}} = 1.822\;{\rm{g/c}}{{\rm{m}}^{\rm{3}}}$$ , Ni-N is $$2.1182\left( {12} \right) - 2.1498\left( {11} \right)\;\acute{\mathring{\mathrm{A}}} ,$$ ∠Ni-N-N is 80.76(4)-82.27(4)°. According to the differential scanning calorimetry data in a range from 295 K to 310 K, there is a thermal anomaly with peaks at T1 = 299.6 K and T2 = 304.7 K. The crystal structural characteristics at 320 K are as follows: space group $$P\overline 3 \,1c,\;a = 9.2491\left( 4 \right)\;\acute{\mathring{\mathrm{A}}} ,\;c = 9.9713\left( 4 \right)\;\acute{\mathring{\mathrm{A}}} ,\;V = 738.72\left( 7 \right)\;{\acute{\mathring{\mathrm{A}}} ^3},\;Z = 2,\;{d_x} = 1.794\;{\rm{g/c}}{{\rm{m}}^3}$$ , Ni-N is $$2.1302\left( {14} \right)\;\acute{\mathring{\mathrm{A}}} $$ , ∠N-Ni-N is 80.96(8)°. With increasing temperature from 90 K to 320 K a decrease in the average Mo-O distance from $$1.769\;\acute{\mathring{\mathrm{A}}} $$ to $$1.725\;\acute{\mathring{\mathrm{A}}} $$ is observed in the structure. The comparative analysis of the interionic N-H…O and C-H…O contacts is carried out. The ex situ powder X-ray diffraction study of the formation process of metal and carbide phases by the [NiEn3]MoO4 thermal decomposition in the presence of LiH in the He atmosphere is performed. At the temperature of 1323 K a Mo2C and MoNi4 phase mixture forms in the first minute. With increasing keeping time the Ni2Mo4Cx phase forms.

Performance of high-velocity aircraft is largely governed by the efficiency of the thermal protection systems used. One of the most complex cases is thermal protection for structural elements in a high-velocity air flow. The elements must ensure high geometrical stability of the surface inside the flow when the profile blunting radii are small. For this case, we analysed the potential of an active lithium hydride-based thermal protection system exploiting the high thermal effects of its phase transitions. We show that the system under consideration may feature characteristics acceptable in practice regarding thermal protection of blunted aerofoils made out of modern heat-resistant materials

The formation of metallic and carbide phases during the thermal decomposition of a mixture of the coordination compound [NiEn3]WO4 (En = ethylenediamine) and LiH in a He atmosphere has been studied by X-ray diffraction. The results demonstrate that heat treatment of the mixture at 410°C for 10 min leads to the formation of a Ni(Cx) interstitial solid solution based on the HCP Ni lattice and a W1 –xNix substitutional solid solution based on the BCC W lattice. Starting at 510°C, a Ni1 –xWx solid solution based on the FCC Ni lattice is also formed. The double carbide Ni2W4Cx appears at 660°C, and Ni6W6Cx forms at 860°C. Under similar conditions (700°C, He), the thermal decomposition of a mixture of NiWO4 and LiH leads to the formation of W and an FCC Ni1 –xWx (x ~ 0.12) solid solution.

The Haber-Bosch process for ammonia (NH3 ) production in industry relies on high temperature and high pressure and is therefore highly energy intensive. In addition, the activity of the solid transition metal-based catalysts used is typically limited by the scaling relation between activation barrier for N2 dissociation and nitrogen-binding energy. Here, an innovative Li-based loop in a liquid alloy-salt catalytic system for ambient-pressure NH3 synthesis from N2 and H2 was developed. The looping process consisted of three reaction steps taking place simultaneously. The first step was the nitrogen fixation by Li in the liquid Li-Sn alloy to form lithium nitride (Li3 N), which floated up and dissolved into the molten salt. The second step was the hydrogenation of the Li3 N to produce NH3 and lithium hydride (LiH) in the molten salt. The third step was the decomposition of the LiH to regenerate Li in the presence of Sn. An average NH3 yield rate of 0.025 μg s-1 was achieved in an 81 h test at 510 °C and ambient pressure. The floating and dissolution of Li3 N realized in the liquid catalytic system enabled circumventing the scaling relation exerted on Li, and the remarkable properties of liquid alloy and molten salt offered extraordinary advantages for NH3 synthesis at ambient pressure.

In this work, we have studied such thermal function of diatomic molecules like hydrogen dimer, carbon monoxide, nitrogen dimer and lithium hydride using improved deformed exponential-type potential (IDEP). To this end, the energy spectra of the IDEP are obtained applying Greene-Aldrich approximation and appropriate coordinate transformation within the framework of non-relativistic quantum mechanics. With calculated energy eigenstates, we have deduced the partition function and such thermodynamic functions like specific heat in constant pressure, enthalpy and Gibbs free energy by employing the Poisson summation formula. We have compared our results with experimental data, and there is a good agreement between them.

This paper reveals the structural information of lithium hydride (LiH) at high pressure. The model potential incorporate coulomb interaction potential, short range interaction and van der Waal's attraction energy within the Hafemeister and Flygare approach and the potential term as effective interionic potential model. Values obtained via this technique for LiH, revealed successful phase transition from B1 or NaCl to B2 or CsCl, The estimated transition pressure is 200 GPa, which is quite consistent with the previously available data from different theoretically techniques.

The computation of molecular excitation energies is essential for predicting photo-induced reactions of chemical and technological interest. While the classical computing resources needed for this task scale poorly, quantum algorithms emerge as promising alternatives. In particular, the extension of the variational quantum eigensolver algorithm to the computation of the excitation energies is an attractive option. However, there is currently a lack of such algorithms for correlated molecular systems that is amenable to near-term, noisy hardware. In this work, we propose an extension of the well-established classical equation of motion approach to a quantum algorithm for the calculation of molecular excitation energies on noisy quantum computers. In particular, we demonstrate the efficiency of this approach in the calculation of the excitation energies of the LiH molecule on an IBM Quantum computer., Physical Review Research, 2 (4), ISSN:2643-1564

Fil: Paredes Mellone, Oscar Ariel. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - Cordoba. Instituto de Fisica Enrique Gaviola. Universidad Nacional de Cordoba. Instituto de Fisica Enrique Gaviola; Argentina. Universidad Nacional de Cordoba. Facultad de Matematica, Astronomia y Fisica; Argentina

Molten mixtures of ytterbium and lithium metals can be used as fluxes for the synthesis of metal hydrides. Reactions of indium and lithium hydride in Yb/Li flux produce Yb~51In13H27 (cubic, Im-3; a = 16.218(6) A, Z = 2). Yb~51In13H27 is an analog of previously reported Ca54In13H27 which was grown from Ca/Li flux. The compound features In@Yb12@H20@Yb30 Bergman-like clusters at the corners and body centers of the cubic lattice. The clusters are connected by a hydride site and disordered ytterbium sites. Magnetic susceptibility measurements indicate the ytterbium is divalent; the compound shows diamagnetic behavior with a Curie tail at lower temperatures attributed to impurities such as traces of Yb3+ that form on crystal surfaces due to slight oxidation.

In this study, we propose a new methodology for lithium hydride electrolysis which can be extended for the extraction of hydrogen isotopes from molten lithium. This new process utilizes a ceramic lithium ion conductor that can be directly immersed in molten lithium to facilitate the electrochemical extraction of hydrogen isotopes in the molten state. The extraction of hydrogen isotopes from lithium is necessary for the safe and reliable operation of fusion reactors that utilize molten metals as a coolant and/or as tritium breeder blanket in the system. A number of technologies for hydrogen isotope extraction from molten lithium have been proposed that can facilitate the extraction of hydrogen isotopes. However, they require a series of complicated mechanical steps (expensive mechanical parts with limited lifetimes) in order to carry out the separation and prevent impurities build up in the extraction process. Our proposed electrochemical process can potentially simplify the isotope extraction process by eliminating many of the mechanical parts and being able to integrate this technology within the fusion reactor to perform the extraction in-line. To determine the feasibility of this process, a proof of concept was demonstrated experimentally utilizing a solid state lithium ion conductor to facilitate the electrochemical extraction of hydrogen and deuterium from lithium in the molten state. The extraction of hydrogen and deuterium from molten lithium was verified during this experiment and indicates this new process is a potential alternative for other processes used for the extraction of hydrogen isotopes. Process modeling was also performed to understand the energy requirements and electrode areas needed for decomposing different concentrations of tritium.

Deuterium and lithium are light elements of high cosmological and astrophysical importance. In this work we report the first detection of deuterated molecules and a search for lithium hydride, 7LiH, at redshift z=0.89 in the spiral galaxy intercepting the line of sight to the quasar PKS1830-211. We used ALMA to observe several submillimeter lines of ND, NH2D, and HDO, and their related isotopomers NH2, NH3, and H2^18O, in absorption against the southwest image of the quasar, allowing us to derive XD/XH abundance ratios. The absorption spectra mainly consist of two distinct narrow velocity components for which we find remarkable differences. One velocity component shows XD/XH abundances that is about 10 times larger than the primordial elemental D/H ratio, and no variability of the absorption profile during the time span of our observations. [...] The second component has XD/XH abundances that are 100 times larger than the primordial D/H ratio, a deepening of the absorption by a factor of two within a few months, and a rich chemical composition, with relative enhancements of N2H+, CH3OH, SO2, and complex organic molecules. We therefore speculate that this component is associated with the analog of a Galactic dark cloud, while the first component is likely more diffuse. Our search for the 7LiH (1--0) line was unsuccessful and we derive an upper limit 7LiH/H2 = 4 x 10^-13 (3sigma) in the z=0.89 absorber toward PKS1830-211. Besides, with ALMA archival data, we could not confirm the previous tentative detections of this line in the z=0.68 absorber toward B0218+357; we derive an upper limit 7LiH/H2 = 5 x 10^-11 (3sigma), although this is less constraining than our limit toward PKS1830-211. We conclude that, as in the Milky Way, only a tiny fraction of lithium nuclei are possibly bound in LiH in these absorbers at intermediate redshift., Accepted for publication in A&A

In recent years, H2 activation at non-transition-metal centers has met with increasing attention. Here, a system in which H2 is activated and transferred to aldimines and ketimines using substoichiometric amounts of lithium bis(trimethylsilyl)amide is reported. Notably, the reaction tolerates the presence of acidic protons in the α-position. Mechanistic investigations indicated that the reaction proceeds via a lithium hydride intermediate as the actual reductant.

As an important parameter of neutronics integral experiment, tritium production rate could not only be used for validation of programs and evaluation database, but was also related to tritium self-consistency after the activation of the sub-critical reactor. This parameter was a key component of the sub-critical reactor design. Four blanket benchmark mockups of a fusion-fission hybrid reactor were established utilizing lithium materials, which consisted of depleted uranium/lithium hydride, uranium/lithium hydride/polyethylene, uranium/lithium hydride/graphite/iron, and uranium/Li-Pb alloy/polyethylene. Based on the Cockcroft–Walton neutron generator, the distribution of tritium production rate by D–T neutrons in the four mockups was evaluated by two pairs of different sizes lithium glass detectors. The distribution was then quantitatively assessed using MCNP5 program and ENDF/B-VII database. The tritium production rates of the mockups with lithium hydride significantly deviated from the experimental results; whereas those of the mockup with lithium-lead alloy were agree well with the experimental results.

The reaction of lithium hydride (LiH) powder with pure water vapor (H2O and D2O) was studied by thermogravimetry and in situ infrared spectroscopy at 298 K over a large pressure range. The mean particle size of LiH is around 27 μm. At very low pressure, the hydrolysis starts with the formation of lithium oxide (Li2O). Then, both Li2O and lithium hydroxide (LiOH) are formed on increasing pressure, thus, creating a Li2O/LiOH bilayer. The reaction takes place through the consumption of LiH and the formation of Li2O at the LiH/Li2O interface and through the consumption of Li2O and the formation of LiOH at the Li2O/LiOH interface. Above 10 hPa, only the monohydrate LiOH·H2O is formed. This hydration reaction of LiOH into LiOH·H2O occurs at a lower pressure (8 hPa) after the first hydration-dehydration cycle. The hydrolysis mechanism proposed in this paper suggests that the diffusion of ionic species across the intermediate Li2O layer is the rate limiting step of the reaction.

Recovery of tritium from plasma-facing components in fusion devices will be vital to future full-scale operation. Liquid, low-Z materials have demonstrated many inherent advantages over solid first wall materials. To this end, a thermal treatment method in the form of a distillation column for extraction of hydrogen isotopes from liquid lithium has been designed, developed, and constructed at the Center for Plasma-Material Interactions at the University of Illinois at Urbana-Champaign. Use of induction heating and lithium condensation stages are the two qualities that set this design apart from other thermal treatment systems. Induction heating capabilities were modeled using the COMSOL Multiphysics software, which were validated when commissioning the physical heater module. Proof-of-concept tests were performed in the prototype column, which were undertaken as batch processes to investigate the efficacy with which the column could remove hydrogen gas from lithium-rich and lithium hydride-rich samples. All of the tests reported used lithium hydride as a surrogate for lithium deuteride and lithium tritide. The design process and results from the initial tests will be discussed, along with the envisioned placement of this treatment scheme in a fully-functional lithium loop.

The solid reaction of lithium hydride and lithium hydroxide in lithium hydride pellet is first directly observed at normal ambient condition after 4 years storage. Layer-by-layer XPS results show that LiOH hydrolysis layer quickly forms on the LiH surface, LiOH reacts with bulk LiH to form Li2O and H2. Due to the great H2 outgassing after long time conservation, bubbling problem actually exists during the practical long-time preserving period. Using CO2 as pre-treatment gas during the LiH sample preparation process is a feasible way to prevent LiH sample from bubbling after long storage period. Moreover, Li2CO3 shows possible delay effect on the solid reaction of LiOH with LiH in this work, thus preserving LiH sample in CO2 containing atmosphere might also be an prospective way to protect the sample from further corrosion.

The concept of light activation for triggering hydrogen release or uptake in hydrogen storage materials was investigated with the aid of gold (Au) nanoparticles dispersed at the surface of typical hydrides including magnesium hydride (MgH2 ), lithium hydride (LiH) and sodium alanate (NaAlH4 ). Upon Xe lamp illumination, the overall temperature of the materials reached ca. 100 °C owing to the plasmonic heating effect of the Au nanoparticles. Direct-heat-driven hydrogen storage at the same temperature with a conventional electrical furnace was found to be less effective with a smaller fraction of hydrogen released from Au/LiH and no phase conversion for Au/NaAlH4 or for Au/Mg under hydrogen pressure. The better efficiency of the observed light-driven hydrogen storage is attributed to the higher temperature in the vicinity of the Au nanoparticles owing to their plasmonic effect. With further improvements, light-activated hydrogen storage could lead to an effective approach for hydrogen uptake and release from hydrides at low temperatures.

First principles calculations have been carried out to analyze structural stability of lithium hydride (LiH) in NaCl phase using the full potential linearized augmented plane wave (FP-LAPW) method within the framework of density functional theory (DFT). Calculations have been extended to physiosorbed H-atom compounds LiH·H 2 , LiH·3H 2 and LiH·4H 2 . The obtained results are discussed in the paper. The results for LiH are in excellent agreement with earlier reported data. The obtained direct energy band gap of LiH is 3.0 eV which is in excellent agreement with earlier reported theoretical band gap. The electronic band structure plots of the hydrogen adsorbed compounds show metallic behavior. The elastic constants, anisotropy factor, shear modulus, Young's modulus, Poisson's ratio and cohesive energies of all the compounds are calculated. Calculation of the optical spectra such as the real and imaginary parts of dielectric function, optical reflectivity, absorption coefficient, optical conductivity, refractive index, extinction coefficient and electron energy loss are performed for the energy range 0–15 eV. The obtained results for LiH·H 2 , LiH·3H 2 and LiH·4H 2 , are reported for the first time. This study has been made in search of materials for hydrogen storage. It is concluded that LiH is a promising material for hydrogen storage.

Green synthesis of nanocarbons from greenhouse gas CO2 has been achieved by introducing lithium hydride into CO2 system. However, the role of lithium hydride in determining the morphology and microstructure of nanocarbons is not revealed. Herein, the morphology and porosity of nanocarbons are found to be related to particle sizes of LiH. Gas blowing velocities of H2 and CO2, increased with the decreasing particle size of LiH, and their distribution are revealed to the most important factors for the morphology and porosity of nanocarbons. The understanding of the roles of lithium hydride in green synthesis of nanocarbons may shed light on the design and large-scale synthesis of nanomaterials with desired morphology and microstructure.

We complete the formulation of the standard model of first star formation by exploring the possible impact of $\mathrm{LiH}$ cooling, which has been neglected in previous simulations of non-linear collapse. Specifically, we find that at redshift $z\gtrsim 5$, the cooling by $\mathrm{LiH}$ has no effect on the thermal evolution of shocked primordial gas, and of collapsing primordial gas into minihaloes or relic HII regions, even if the primordial lithium abundance were enhanced by one order of magnitude. Adding the most important lithium species to a minimum network of primordial chemistry, we demonstrate that insufficient $\mathrm{LiH}$ is produced in all cases considered, about $[\mathrm{LiH/Li}]\sim 10^{-9}$ for $T\lesssim 100$ K. Indeed, $\mathrm{LiH}$ cooling would only be marginally significant in shocked primordial gas for the highly unlikely case that the $\mathrm{LiH}$ abundance were increased by nine orders of magnitude, implying that $all$ lithium would have to be converted into $\mathrm{LiH}$. In this study, photo-destruction processes are not considered, and the collisional disassociation rate of $\mathrm{LiH}$ is possibly underestimated, rendering our results an extreme upper limit. Therefore, the cooling by $\mathrm{LiH}$ can safely be neglected for the thermal evolution of Population~III star-forming gas., 10 pages, 7 figures, Accepted for publication in MNRAS, Changes: The implementation of the HD cooling function is changed without affecting the results, and the critical densities of molecular coolants are corrected (Section 2.2). A comment on the effect of LiH cooling in the high density regime is included (Section 3.1.3)

Hierarchical porous carbon (HPC) has become increasingly important in tackling global environmental and energy-related challenges. However, its wide utilization is still limited by the complicated and environment-unfriendly synthesis process. Herein, we report a green and facile strategy to synthesize HPC from abundant metal carbonates without any emission of CO2 or/and noxious gases. The sponge-like HPC synthesized from reacting lithium carbonate (Li2CO3) with lithium hydride (LiH) exhibits high specific surface area and porosity, enabling high-performance lithium storage. The Li2CO3-derived HPC achieves a reversible capacity of ∼1750 mA h g−1 at a current density of 0.2 A g−1, among the highest reversible lithium storage capacities for HPCs. Moreover, excellent cycling stability and superior rate performance are demonstrated with a high capacity of 505 mA h g−1 even at 4.0 A g−1 over 2000 stable cycles. Such a rational and environment-friendly strategy might pave the way for the large-scale synthesis and utilization of HPCs in high-performance energy storage.

Silicon monoxide (SiO) based materials are the most widely used high-capacity anode materials for commercialized lithium-ion batteries. However, their low initial Coulombic efficiency (ICE) hinders their full potential as anode materials for lithium-ion batteries. Here, we demonstrate that Li metal-free dehydrogenation-driven prelithiation employing lithium hydride (LiH) could improve the ICE of SiO up to 90.5%. Lithium liberated from LiH served as a source for preemptive formation of lithium silicate phases that are the main reason for the poor ICE of SiO, leading to three-dimensionally networked Si/lithium silicate nanocomposites, which were visualized by laser-assisted atom probe tomography (LA-APT) and scanning transmission electron microscopy (STEM). The prelithiated SiO delivered a capacity of 1203 mAh g−1 with an ICE of 90.5% without any degradation in other electrochemical performance. The improved ICE of prelithiated SiO made possible to enhance the energy density of full cell (37 mAh) by 50% compared to that adopting pristine SiO with an excellent cycle performance over 800 cycles.

Lithium hydride is a solid, unstable substance. It reacts violently with water to produce strong liquor (LiOH) and hydrogen. It may self-ignite. It is used in the metallurgical, pharmaceutical, ceramic and chemical industries. Lithium hydride is strongly toxic. It is irritating and corrosive to the to the skin, damaging the mucous membranes of the respiratory tract. May cause eye burns and loss of vision. Harmful to the digestive tract, nervous system and kidneys. Exposure limit values for lithium hydride is NDS – 0.025 mg/ m3. The aim of the study was the amendment of the method for determining concentrations of lithium hydride in the air at workplaces in the range of 1/10 to 2 NDS values, in accordance with the requirements of Standard No. EN 482. The developed method for determining involves: collect of lithium hydride contained in the air on a membrane filter, mineralization of the filter using concentrated nitric acid, and the determination lithium in the solution prepared for analysis by atomic absorption spectrometry with lean flame air-acetylene ( F-AAS). This method enables the determination of lithium in concentration range of 0.05  3.50 g/ml. The lithium calibration curve obtained is characterized by correlation coefficient R2 = 1.0000. The detection limit of lithium (LOD) is 2 ng/ml, and the limit of quantification (LOQ) is 5 ng/ml. Determined coefficient of recovery is 1.00. The developed method enables the determination of lithium hydride in workplaces air in the concentration range of 0.0008  0.056 mg/m3 (for a 720 l air sample) which represents 0.03  2.24 NDS. The method of determining of lithium hydride has been recorded as an analytical procedure (appendix).

Hydrogen is touted as one of the solutions for future energy requirements. Metal hydrides typically studied for their high hydrogen capacity can be used as a thermal storage system by taking advantage of their endothermic/exothermic reactions with hydrogen. This allows the harnessing of solar energy by utilising thermal storage to alleviate its intermittent nature. Lithium amide (LiNH 2 ), imides (Li 2 NH) and nitrides (Li 3 N) have been widely studied for their hydrogen storage at relatively low operating temperatures, typically suited for mobile applications. However, little work has been done involving the imide to nitride reaction of lithium-based materials due to their high temperature range. The following techniques were used to characterise this system: temperature programmed desorption (TPD), temperature programmed photographic analysis (TPPA), x-ray diffraction (XRD) and pressure-composition-temperature (PCT) measurements. TPD results revealed that only a single-step reaction occurred between 100 and 600 °C. TPPA revealed that having a molten solid solution of the sample, depreciated the reversibility of hydrogen absorption and desorption. The molten sample behaved quite vigorously in TPPA measurements and consequently blocked sample filters and sintering sample cell walls; creating engineering problems at higher temperatures. The results revealed that for reactions involving Li 2 NH and lithium hydride (LiH), the temperature range required for thermal storage is above the melting point of the system. The diffusion and absorption of hydrogen through stainless steel would also occur in the sample cells used, resulting in further problems. The reaction pathway of Li 2 NH and LiH was also found to be far more complex than generally reported: XRD revealed that the expected final product of Li 3 N could not be identified, instead a lithium imide-nitride hydride phase (Li 4‑2 x N 1‑ x H 1‑ x (NH) x ) was identified as the final product of this system. PCT measurements were conducted to identify the kinetic and thermodynamics of this system, but because of the molten solid-solution problem, an accurate result could not be obtained.

A reactional mechanism describing the hydrolysis of lithium hydride (LiH) under moist atmosphere is proposed and modeled. It involves the formation of lithium oxide (Li2O) at low vapor pressure and both lithium oxide and lithium hydroxide (LiOH) at higher vapor pressures, with diffusion of water in these layers. A numerical model based on this mechanism is implemented with COMSOL Multiphysics to simulate the hydrolysis of LiH particles in open system (constant water vapor pressure). Kinetic parameters such as rate constant of reactions and diffusion coefficient of water in Li2O and LiOH are first fitted against experimental data. The best agreements are obtained when the diffusion coefficient of water is 10 times higher in LiOH than in Li2O. The resulting model accurately predicts the hydrolysis rates experimentally measured for a wide range of water vapor pressures (0.3–17 Pa). The hydrolysis mechanisms are compatible with a Li2O production limited by water diffusion and a LiOH production governed by the kinetics. Finally, simulation suggest that the thickness of the Li2O layer does not depends much on the water vapor pressure whereas that of LiOH increases drastically at high water vapor pressures.

In this paper, the hydrogen storage properties of the LiNH2 LiH system doped with K2TiF6 were investigated and discussed. Interestingly, the hydrogen storage properties are significantly enhanced by introducing K2TiF6 into the LiNH2 LiH system. By doping 5 mol% K2TiF6 in the LiNH2 LiH system, we obtain the hydrogen desorption peak temperature (233 °C) at a heating rate of 10 °C min−1, which is approximately 66 °C lower than that of the pristine LiNH2 LiH system. Moreover, the system begins to desorb H2 at 75 °C, which is approximately 124 °C lower than in the pristine LiNH2 LiH system. The isothermal desorption kinetics at 250 °C and 300 °C clearly reflects the dramatically improved kinetic properties. Additionally, the reversibility of the LiNH2 LiH system can be drastically enhanced by adding K2TiF6. We propose that the dehydrogenation property of the K2TiF6-doped LiNH2 LiH sample is improved by the synergetic effects of K, Ti and F.

The possibility of formation of moving exotic protonium atoms at channeling of antiprotons in an ionic crystal of lithium hydride is proposed and investigated. For this purpose the probability of proton capture by moving antiprotons channeling in crystallographic H−–(1 1 1) planes and H−–(1 1 0) axes in ionic LiH crystal was calculated. It has been shown that the process of formation of moving exotic pp– protonium atoms regarding antiprotons velocities has a resonance character depending on quantum states of these protonium atoms. It was shown that at the capture to higher quantum states the magnitude of resonance peaks increases and the resonance velocities decreases.

The present research work involved the reaction of 2,3-dihydro-1,4-benzodioxin-6-amine (1) and benzenesulfonyl chloride (2) under dynamic pH control at 10 using aqueous Na2CO3. This reaction yielded 2,3-dihydro-1,4-benzodioxin-6-yl)benzenesulfonamide (3), which was further substituted at N-position with various alkyl/aryl halides (4a – 4m) in N,N-dimethylformamide and catalytic amount of lithium hydride to obtain N-substituted (2,3-dihydro-1,4-benzodioxin-6-yl)benzenesulfonamides (5a – 5m). The projected structures of the synthesized derivatives were confirmed using various spectral techniques (IR, 1H NMR and EIMS). The synthesized derivatives were screened for antibacterial potential and inhibitory activity against lipoxygenase enzyme.

In this study, lithium hydride (LiH) and its hydrolysis products were investigated non-destructively with neutron radiography and neutron computed tomography. Relative neutron transmission intensities ( I / I 0 ) were measured for LiOH, Li 2 O and LiH, and their linear attenuation coefficients calculated from this data. We show that 7Li is necessary for creating large differences in I / I 0 for facile identification of these compounds. The thermal decomposition of LiOH to Li 2 O was also observed with neutron radiography. Computed tomography shows that the samples were fairly homogeneous, with very few macroscopic defects. The results shown here demonstrate the feasibility of observing LiH hydrolysis with neutron imaging techniques in real time.

In this study, the superior effect of RbF on reducing the hydrogen desorption operating temperature of the Li N H system was demonstrated. By doping 5 mol% RbF in the LiNH2 LiH system, we obtain the lowest hydrogen desorption peak temperature (211 °C) at a heating rate of 5 °C/min, which is approximately 69 °C lower than that of the pristine LiNH2 LiH system. Moreover, the system starts to desorb H2 at 120 °C, which is the lowest hydrogen desorption onset temperature. The hydrogen desorption peak and onset temperatures can be further decreased by doping more RbF. It is proposed that the RbH produced during heat treatment improves the dehydrogenation properties of the RbF-doped LiNH2 LiH sample.

Compared to common density functionals, ab initio wave function methods can provide greater reliability and accuracy, which could prove useful when modeling adsorbates or defects of otherwise periodic systems. However, the breaking of translational symmetry necessitates large supercells that are often prohibitive for correlated wave function methods. As an alternative, this paper introduces the regional embedding approach, which enables correlated wave function treatments of only a target fragment of interest through small, fragment-localized orbital spaces constructed using a simple overlap criterion. Applications to the adsorption of water on lithium hydride, hexagonal boron nitride, and graphene substrates show that regional embedding combined with focal-point corrections can provide converged CCSD(T) (coupled-cluster) adsorption energies with very small fragment sizes.

Lithium hydride (LiH) is a unique, ionic compound with applications in a variety of industries. Unfortunately, LiH is very reactive toward H2O even at ppm levels, forming oxide (Li2O) and hydroxide (LiOH) corrosion layers while outgassing H2. An effective means to eliminate unwanted outgassing is vacuum-heating to convert LiOH into Li2O, although subsequent re-exposure to moisture during transport/handling reconverts some Li2O back to LiOH. A corrosion growth model for previously vacuum-baked LiH is necessary for long-term prediction of the hydrolysis of LiH. In this work, a para-linear hydroxide corrosion growth model is proposed for the reaction of previously vacuum-baked LiH samples with moisture. This model, composed of two competing diffusion reaction fronts at the LiOH/Li2O and Li2O/LiH interfaces, is validated experimentally by subjecting a previously vacuum-baked polycrystalline LiH sample to 35 ppm of H2O at room temperature while monitoring the corrosion growth as a function of time with diffuse-reflectance infrared Fourier transform (DRIFT) spectroscopy. The para-linear growth model for the hydrolysis of previously vacuum-baked LiH proposed in this report can also serve as a template for the hydrolysis of other hygroscopic oxides grown on metal or metal hydride substrates.