Mass spectrometric studies of lithium-containing oxides at high temperature

The sublimation and vaporization of various lithium containing oxides have been studied by high temperature mass spectrometry. The installed Knudsen cell apparatus gave some useful information about the vapor species, appearance potentials, partial pressures and heats of reactions involved. The investigated oxides are Li₂O, Li₂O-Al₂O₃, Li₂O-MoO₂ and Li₂O-SiO₂ systems. This paper mainly presents the most recent data for the Li₂O-SiO₂ system. A relationship for the decomposition reaction of ortho-Li₄SiO₄ was deduced. The heat of the reaction was determined by the third law method.The activity of the Li₂O component in the double oxides was estimated from the partial pressures of the vapor species. γ-LiAlO₂ and meta-Li₂SiO₃ showed fairly low activities in comparison with Li₂O oxide. The activity coefficients decreased with the Li₂O mole fraction in the lithium compounds.The heats of formation and atomization of LiO and Li₂O gaseous species were determined.     

Enhancement of thin film tin oxide negative electrodes for lithium batteries

Thin films of pure SnO₂, of the Sn/Li₂O layered structure, and of Sn/Li₂O were fabricated by sputtering method, while a `lithium-reacted tin oxide thin film' was assembled by the evaporation of lithium metal onto a SnO₂ thin film. Film structure and charge/discharge characteristics were compared. The lithium-reacted tin oxide thin film, the Sn/Li₂O layered structure, and the Sn/Li₂O co-sputtered thin films did not show any irreversible side reactions of forming Li₂O and metallic Sn near 0.8 V vs Li/Li⁺. The initial charge retention of the Sn/Li₂O layered structure and Sn/Li₂O co-sputtered thin films was about 50% and a similar value was found for the lithium-reacted tin oxide thin film (more than 60%). Sn/Li₂O layered structure and Sn/Li₂O co-sputtered thin films showed better cycling behavior over 500 cycles than the pure SnO₂ and lithium-reacted tin oxide thin film in the cut-off range from 1.2 to 0 V vs Li/Li⁺.     

Al2O3/K2O-containing non-stoichiometric lithium disilicate-based glasses

The crystallisation kinetics of experimental glasses in 3 different systems: (A) Li₂O–SiO₂, (B) Li₂O–Al₂O₃–SiO₂ and (C) Li₂O–K₂O–Al₂O₃–SiO₂ were studied under non-isothermal conditions. The DTA results revealed a stronger tendency to crystallisation of binary compositions in comparison to the ternary and quaternary compositions comprising Al₂O₃ and K₂O which present the lower crystallisation, i.e. the crystallisation propensity follows the trend A > B > C. The devitrification process in the Li₂O–SiO₂ and Li₂O–Al₂O₃–SiO₂ systems began earlier and the rate was higher in comparison to that of glasses in the quaternary Li₂O–K₂O–Al₂O₃–SiO₂ system. Thus, addition of Al₂O₃ and K₂O to glasses of Li₂O–SiO₂ system was demonstrated to promote glass stability against crystallisation. However, the activation energy for crystallisation was shown to depend also on the SiO₂/Li₂O ratio with the binary system showing a decreasing trend with increasing SiO₂/Li₂O ratio, while the opposite tendency was being observed for compositions with added Al₂O₃ and K₂O.     

Kinetic and mechanistic studies of the iridium(III) catalyzed oxidation of sulphanilic acid by diperiodatocuprate(III) in aqueous alkaline medium

The effect of La₂O₃, K₂O and Li₂O on the properties and catalytic performance of silica-supported nickel catalysts for the hydrogenation of m-dinitrobenzene was investigated. The catalysts promoted with La₂O₃, Li₂O and K₂O showed better catalytic performance than the catalyst without promotion, especially the ones co-promoted with La₂O₃ and K₂O or Li₂O.     

DVM Xα calculations on the electronic structure of “superalkali” cations

The electronic structure of the radicals Li₂F, Li₃O, Li₄N, Li₂Cl, Li₃S, Li₄P, Na₂F, Na₃O, Na₄P, Na₂Cl, Na₃S, Na₄P, Cs₂F, Cs₂Cl and NH₄ were calculated by the discrete variational Xα method. In all cases the electron affinity of the cation is less than that of the ligand alkali cations, thus giving rise to the name “superalkali”.     

Etudes electrique et Raman de borotungstates et de boromolybdates de lithium vitreux

Conductivity studies of glasses obtained from the B₂O₃Li₂OLi₂MoO₄ and B₂O₃Li₂OLi₂WO₄ systems have been carried out. The presence of the transition element in tetrahedral coordination and with two different oxidation states is discussed. A Raman spectroscopy study shows that the MoO₄ or WO₄ tetrahedra are slightly compressed by the network forming lattice.     

Interaction in the Li2Mo3O10-CO(NH2)2-H2O system at 25°C

The solubilities and solid phases in the Li₂Mo₃O₁₀-CO(NH₂)₂-H₂O system at 25°C are studied. A compound of composition Li₂Mo₃O₁₀ · 6CO(NH₂)₂ · 4H₂O and lithium trimolybdate decahydrate Li₂Mo₃O₁₀ · 10H₂O are found to exist. The Li₂Mo₃O₁₀ · 6CO(NH₂)₂ · 4H₂O ray crosses the solubility isotherm, which indicates the congruent solubility of the double compound in water. The density, refractive index, dynamic viscosity, surface tension, electrical conductivity, and pH of saturated solutions of the system are determined. The molar volume, equivalent electrical conductivity, reduced conductivity, and solution ionic strength isotherms are calculated. A strong correlation between all the property isotherms and the solubility is observed.     

New electrolytes using Li2O or Li2O2 oxides and tris(pentafluorophenyl) borane as boron based anion receptor for lithium batteries

A new system of electrolytes has been developed and studied for lithium-ion batteries. This new system is based on the interactions between Li₂O or Li₂O₂ and tris(pentafluorophenyl) borane (TPFPB) in carbonate based organic solvents. This opens up a completely new approach in developing non-aqueous electrolytes. In general, the solubility of Li₂O or Li₂O₂ is very low in organic solvents and the ionic conductivities of these solutions are almost undetectable. By adding certain amount of tris(pentafluorophenyl) borane (TPFPB), one type of boron based anion receptors (BBARs), the solubility of Li₂O or Li₂O₂ in carbonate based solvents was significantly enhanced. In addition, the Li⁺ transference numbers of these new electrolytes measured were as high as 0.7, which are more than 100% higher than the values for the conventional electrolytes for lithium-ion batteries. The room-temperature conductivities are around 1 × 10⁻³ S/cm. These new electrolytes are compatible with LiMn₂O₄ cathode for lithium-ion batteries.     

Answer to the Comment submitted by R. Niewa and D. A. Zherebtsov on the Paper “Synthesis and Electrochemical Study of Antifluorite‐type Phases in the Li‐M‐N‐O (M = Ti,V) Systems” [1]

In the reaction conditions leading to γ‐Li₇VN₄, no ordered solid solution γ‐Li₇VN₄–Li₂O seems to exist but rather a mixture of two phases: γ‐Li₇VN₄ and a lithium vanadium oxynitride with the disordered anti‐fluorite structure. Even though the trend may be different in the case of β‐Li₇VN₄–Li₂O, neutron diffraction experiments would be desirable to confirm/dismiss these assumptions, as they would allow to determine the number of phases and polymorphs present and the degree of Li/V or N/O order, if any.     

Zur Kenntnis der Systeme Li2O/CoO und Li2O/ZnO

On the Systems Li₂O/CoO and Li₂O/ZnO According to powder photographs the systems Li₂O/CoO and Li₂O/ZnO are so far similar as the Li-richest phase in near ?Li₄MO₃”?. Single crystal investigations lead to a pseudocubic, trigonal unit cell; a = 13.14, c = 7.99 Å (Zn); a = 13.10, c = 7.98 Å (Co). The oxygen form a cubic closest packing. Surprisingly there is obviously no completely ordered arrangement of cations. In spite of single crystal data the extent of the phases is still unknown.     

Ein neues Periodat Zum Aufbau von K9Li3I2O13 = K9Li3O[IO6]2

A Novel Periodate: On the Structure of K₉Li₃I₂O₁₃ = K₉Li₃O[IO₆]₂ New obtained are weakly dichroitic (pale yellow/bluish) single crystals of K₉Li₃I₂O₁₃ by reaction of KIO₄, K₂O, and Li₂O (KIO₄:K₂O:Li₂O = 1:1:1.5; 800°C, 42 d). Space group P62c, Z = 2, a = 954.9 pm, c = 1172.2 pm, R = 6.2%, Rw = 5.6%, 957 symmetry independend I₀(hkl), MoKα . Characteristic for this structure are ?isolated”? O^2? and octahedral groups [IO₆]. The crystal structure has been determind. The Madelung Part of Lattice Energy, MAPLE, is calculated and discussed.     

Ab initio calculations on the interaction of oxygen containing ligands with alkali cations. The system H2CO/Li+

Ab initio calculations on formaldehyde/Li⁺ complexes are presented. The most stable arrangement is characterized by an energy of interaction of 43.2 kcal/mole, C_2v symmetry and an oxygen—lithium distance of R_OLi = 1.77 Å. A detailed analysis of the electron density function gives proof of the electrostatic nature of the complexes H₂O/Li⁺ and H₂Co/Li⁺ and shows extensive mutual polarization. The failure of the semi-empirical method to predict the changes in electron density at the Li⁺ cation correctly is explained.     

A study of the formation of LiNbO3 in the system Li2CO3Nb2O5

The formation process of LiNbO₃ in the system Li₂CO₃Nb₂O₅ was discussed from the results of non-isothermal or isothermal TG experiments and X-ray analysis. The mixture Li₂CO₃ and Nb₂O₅ in mole ratios of 1:3, 1:1 or 3:1 was heated at a rate of 5°C min^?1 or at various temperatures fixed in the range 475 to 677°C. If the system has a composition of Li₂CO₃ + 3Nb₂O₅ or 3Li₂CO₃ + Nb₂O₅, the reaction between Li₂CO₃ and Nb₂O₅ proceeds with CO₂ evolution to form LiNbO₃ at ca. 300–600°C, but Nb₂O₅ or Li₂CO₃ remains unreacted. A composition of Li₂CO₃ + Nb₂O₅ gives LiNbO₃ at 300–700°C. The diffusion of Li₂O through the layer of LiNbO₃ is rate-controlling with an activation energy of 51 kcal mol^?1. The reaction between LiNbO₃ and Nb₂O₅ gives LiNb₃O₈ at 600–700°C. At 700–800°C, a slight formation of Li₃NbO₄ occurs by the reaction between LiNbO₃ and Li₂O at the outer surface of LiNbO₃ and the Li₂O component of Li₃NbO₄ diffuses toward the boundary of the LiNb₃O₈ layer through the LiNbO₃ layer. The single phase of LiNbO₃ is formed above 850°C.     

Loss of metallicity in metal rich lithium oxide clusters

Mixed lithium-lithium oxide aggregates are experimentally obtained from unimolecular evaporative cascades starting at metal rich Li _p ⁺ (Li₂O)_n species and ending with the stoichiometric limit Li⁺(Li₂O)_n, for several sizes of the oxide part (Li₂O)_n with 0 ≤ n ≤ 8. The results show evidence of the vanishing of the properties of the quantum metallic droplet i.e. shell closing and odd-even alternation, portrayed in the dissociation energy, with increasing size of the oxide component. The competition between monomer and dimer lithium evaporation from the heated metal rich Li _p ⁺ (Li₂O)_n species points out the influence of the perturbation induced by the oxide component on the mixed metal oxide clusters.     

Theoretical prediction for the structures of gas phase lithium oxide clusters: (Li2O)n (n = 1–8)

We apply genetic algorithm combining directly with density functional method to search the potential energy surface of lithium‐oxide clusters (Li₂O)_n up to n = 8. In (Li₂O)_n (n = 1–8) clusters, the planar structures are found to be global minimum up to n = 2, and the global minimum structures are all three‐dimensional at n ≥ 3. At n ≥ 4, the tetrahedral unit (TU) is found in most of the stable structures. In the TU, the central Li is bonded with four O atoms in sp³ interactions, which leads to unusual charge transformation, and the probability of the central Li participating in the bonding is higher by adaptive natural density partitioning analysis, so the central Li is in particularly low positive charge. At large cluster size, distortion of structures is viewed, which breaks the symmetry and may make energy higher. The global minimum structures of (Li₂O)₂, (Li₂O)₆, and (Li₂O)₇ clusters are the most stable magic numbers, where the first one is planar and the later both have stable structural units of tetrahedral and C_4v. © 2012 Wiley Periodicals, Inc.     

A First‐Cycle Coulombic Efficiency Higher than 100 % Observed for a Li2MO3 (M=Mo or Ru) Electrode

The lithiation/de‐lithiation behavior of a ternary oxide (Li₂MO₃, where M=Mo or Ru) is examined. In the first lithiation, the metal oxide (MO₂) component in Li₂MO₃ is lithiated by a conversion reaction to generate nano‐sized metal (M) particles and two equivalents of Li₂O. As a result, one idling Li₂O equivalent is generated from Li₂MO₃. In the de‐lithiation period, three equivalents of Li₂O react with M to generate MO₃. The first‐cycle Coulombic efficiency is theoretically 150 % since the initial Li₂MO₃ takes four Li⁺ ions and four electrons per formula unit, whereas the M component is oxidized to MO₃ by releasing six Li⁺ ions and six electrons. In practice, the first‐cycle Coulombic efficiency is less than 150 % owing to an irreversible charge consumption for electrolyte decomposition. The as‐generated MO₃ is lithiated/de‐lithiated from the second cycle with excellent cycle performance and rate capability.     

Lithium transport within the solid electrolyte interphase

A LiClO₄ SEI film grown on copper was examined with time-of-flight secondary ion mass spectrometry. The SEI porosity profile and Li⁺ transport processes within the SEI were studied with isotopically labeled ⁶LiBF₄ electrolyte. An ~ 5 nm porous region, into which electrolytes can easily diffuse, was observed at the electrolyte/SEI interface. Below the porous region, a densely packed layer of Li₂O and/or Li₂CO₃ prevents electrolyte diffusion, but Li⁺ transports through this region via ion exchange.     

Lithiated Clusters from Primary Silylphosphanes and Silylarsanes: Spherical Bodies with and without Li2O Filling

Molecular clusters with archimedean and platonic shape , which in order to build a closed polyhedron, spontaneously eliminate H₂ or voluntarily encapsulate Li₂O as a “cluster nucleus”, result from the dilithiation of primary silylphosphanes and silylarsanes with BuLi. Thus, the first mixed-valent, decameric P₁₀Li₁₆ cluster 1 was obtained from iPr₃SiPH₂ and tBuLi (molar ratio 1:2) with strict exclusion of LiOH and Li₂O, whereas partial metalation in the presence of LiOH initially leads to a dodecameric, Li₂O-containing cluster 2 , from which the three-shell cluster 3 with a [Li₆O]⁴⁺ core is obtained.     

Recycling of Primary Lithium Batteries Production Residues

Production waste of primary lithium batteries constitutes a considerable secondary lithium feedstock. Although the recycling of lithium batteries is a widely studied field of research, the metallic residues of non-rechargeable lithium battery production are disposed of as waste without further recycling. The risks of handling metallic Li on a large scale typically prevent the metal from being recycled. A way out of this situation is to handle Li in an aqueous solution, from where it can be isolated as Li₂CO₃. However, the challenge in hydrometallurgical treatment lies in the high energy release during dissolution and generation of H₂. To reduce these process-related risks, the Li sheet metal punching residues underwent oxidative thermal treatment from 300 to 400 °C prior to dissolution in water. Converting Li metal to Li₂O in this initial process step results in an energy release reduction of ∼70 %. The optimal oxidation conditions have been determined by experimental design varying three factors: temperature, Li metal sheet thickness, and residence time. With 96.9±2.6 % almost the entire Li amount is converted to Li₂O, after 2.5 h treatment at 400 °C for a Li sheet thickness of 1.99 mm. Final precipitation with CO₂ yields 85.5±3.0 % Li₂CO₃. Using pure Li sheets, the product Li₂CO₃ is obtained in battery-grade quality (>99.5 %). Non-precipitated Li is recirculated into the process on the stage of dissolving Li₂O, thus avoiding loss of material.     

An infrared and Raman study of new lonic-conductor lithium glasses

New vitreous fast ionic conductors in the system B₂O₃Li₂OLiCl are described. The conductivity of these glasses increases with the Li₂O and particularly with the LiCl contents. A Raman and infrared study undertaken to elucidate the “structure” of the glasses and the conduction mechanism indicates that the structure consists of a “covalent” boron-oxygen network, in which LiCl is “diluted” without producing detectable interactions with the latter.