High Lithium Content Research Articles

On the growth of Li2CO3 dendrites in nickel–cadmium industrial batteries

Abstract A large amount of Li 2 CO 3 dendrites has been detected on positive electrodes in Ni–Cd industrial pocket plate batteries, intended to work in stationary applications, after 3 years in float charge. The lattice parameters were refined to a =8.353(1) A, b =4.974(1) A, c =6.194(1) A and β =114.6(1)° [monoclinic], which is in complete agreement with structural data reported in the literature. Oxidation of graphite present in the positive active material is enhanced at elevated temperatures, and at high anodic potentials. This results in an extremely high carbonate concentration in the active material, as well as in the electrolyte. The high carbonate content, in combination with the relatively high lithium concentration present in both electrolyte and positive electrode, is very likely to be the reason for the formation of the Li 2 CO 3 dendrites. As this process continues, agglomerates of the dendrites in combination with attached β -Cd(OH) 2 and graphite may generate short circuits between the positive and the negative electrodes.

Mixed hydrothermal fluids and the origin of the Martian soil

The Martian soil consists mainly of weathered basaltic rock and a “salt” component enriched in volatile and mobile elements, primarily sulfur, chlorine, sodium, and potassium. Since the discovery of this mobile element component by the Viking X‐ray fluorescence spectrometer, volcanic aerosols have been considered a likely source for these enrichments. Alternative sources of the mobile element component are fluids supplied to the surface by hydrothermal processes related to impact craters and volcanism. We show that a mixed hydrothermal fluid model can successfully explain the composition of the mobile element component of the soil. This model is constructed using terrestrial analogs constrained by the Viking and Pathfinder measurements of the Martian soil chemistry. The potential hydrothermal fluid contributions to the soil are tightly constrained because the relative abundances of the mobile elements in hydrothermal fluids are nearly constant. The two end‐member types of hydrothermal fluids considered in the model are the neutral‐chloride and the acid‐sulfate type. The neutral‐chloride fluids have high Cl and Na contents and a significant amount of K, but their S abundance relative to Cl (S/Cl ratio) is too low to match the Martian soil. However, acid‐sulfate hydrothermal systems characterized by substantial vapor transport and high S/Cl ratios are likely on Mars due to the low abundance of water. Indeed, as the availability of water declines in a hydrothermal system, the neutral‐chloride system can evolve to a vapor‐dominated acid‐sulfate system. A combination of the two types of fluids can quantitatively explain the S and Cl abundance in the soil and provide reasonable abundances of other mobile elements, including Na, K, and Br, without predicting an excess of any element measured in the soil. However, the hydrothermal fluids are unlikely to be involved in the formation of the magnetic minerals in the soil because the Fe contents of the fluids are too low. Although the acid‐sulfate fluids have Fe concentrations a factor of 100 larger than the neutral‐chloride fluids, the acid‐sulfate fluids would contribute less than 1% of the total Fe in the soil. The volcanic aerosol models are poorly constrained in contrast to the hydrothermal fluid models because in volcanic aerosols the relative abundances of the mobile elements are highly variable. Therefore, while volcanic aerosols can explain the mobile element component of the soil, significant contributions from other sources cannot be excluded. Determining the relative contributions of hydrothermal components compared to volcanic aerosols will require measurements in the Martian soil of trace elements that provide signatures of the hydrothermal fluids, such as high lithium contents that are associated with neutral‐chloride fluids.

The Lithium-rich supergiant HD172365

The F-type supergiant HD172365 was discovered by Luck (1982) to be a high Li abundance star. We find that the lithium abundance in this star is log A(Li) = 2.9 from a careful spectroscopic study. This value is larger than the abundance derived by Luck. We discuss the properties of this supergiant and tentatively conclude that HD172365 may, in fact, be a post-blue straggler star with a mass ∼2 times greater than the “turn-off point” mass for the open cluster IC 4756, of which HD172365 is a member. The star is formed by a merger of a close binary system. This conclusion is supported by, for example, its large projected rotational velocity, solar carbon abundance and high lithium content.

Lanthanide Complexes of the α-1 Isomer of the [P2W17O61]10-Heteropolytungstate: Preparation, Stoichiometry, and Structural Characterization by183W and31P NMR Spectroscopy and Europium(III) Luminescence Spectroscopy

The alpha-1 and alpha-2 [P(2)W(17)O(61)](10)(-) isomers, derivatives of the Wells-Dawson molecule, [alpha-P(2)W(18)O(62)](6)(-), may be useful ligands for stabilizing high-valent metal ions and lanthanides and actinides. However, the potential utility of the [alpha1-P(2)W(17)O(61)](10)(-) ligand has not been realized. Specifically, for the lanthanides, the stoichiometry, structure, and purity of the lanthanide complexes of the [alpha1-P(2)W(17)O(61)](10)(-) isomer are ambiguous. We have prepared lanthanide (Ln) complexes of the [alpha1-P(2)W(17)O(61)](10)(-) isomer in >/=98% isomeric purity, according to (31)P NMR data. (183)W NMR data clearly showed, for the first time, that the C(1) symmetry of the [alpha1-P(2)W(17)O(61)](10)(-) lanthanide complexes was maintained in solution. We determined the stoichiometry of the lanthanide complexes of the [alpha1-P(2)W(17)O(61)](10)(-) isomer in solution by two different methods: a complexometric titration method and excited state lifetime measurements and luminescence titrations for the europium(III) analogue. All experiments show a 1:1 Ln:[alpha1-P(2)W(17)O(61)](10)(-) ratio. The (31)P NMR data showed that the lanthanides with smaller ionic radii (higher charge-size ratio) form stable complexes, even surviving crystallization from hot water. On the other hand, the lanthanum analogues were not stable in solutions of high lithium content. The tetrabutylammonium salt of the [Lu(alpha1-P(2)W(17)O(61))](7)(-) complex showed >/=98% isomeric purity and the C(1) symmetry required for a derivative of [alpha1-P(2)W(17)O(61)](10)(-). Also the tetrabutylammonium cation stabilized the [Lu(alpha1-P(2)W(17)O(61))](7)(-) complex; a mixed tetrabutylammonium, lithium salt was stable in water for weeks according to (31)P NMR spectroscopy.

Lithium Diffusion in Layered Li[sub x]CoO[sub 2

The results of a first principles investigation of lithium diffusion within the layered form of are presented. Kinetic Monte Carlo simulations predict that lithium diffusion is mediated through a divacancy mechanism between and and with isolated vacancies at infinite vacancy dilution. The activation barrier for the divacancy migration mechanism depends strongly on lithium concentration resulting in a diffusion coefficient that varies within several orders of magnitude. We also argue that the thermodynamic factor in the expression of the chemical diffusion coefficient plays an important role at high lithium concentration. ©2000 The Electrochemical Society

Lithium Manganese Nickel Oxides Lix ( MnyNi1 − y ) 2 − x O 2: II. Electrochemical Studies on Thin‐Film Batteries

In a lithium thin‐film battery, the reversible discharge capacity of a cathode deposited by rf magnetron sputtering and postannealed at 750°C under could be increased by 80% to 136 μAh/mg when cycled between 4.8–2.5 V instead of 4.2–2.5 V. An 82 atom % (14 vol %) cathode prepared from a rf magnetron sputter‐deposited film that was annealed at 700°C under supplied a reversible discharge capacity of 146 μAh/mg between 5.3–1.5 V. For a given lithium concentration in the cathode during cycling, the magnitude of the chemical potential of sites on the lithium layers (3a sites) in both rhombohedral cathode phases decreased whenever the charge cutoff voltage was raised. This thermodynamic change is attributed to the migration of transition metal ions from the 3b layer sites to vacancies on the lithium layers at high potentials. These transition metal ions also explain the kinetic limitations the cathodes exhibited at higher current densities. Only one rhombohedral phase could be detected by ex situ X‐ray diffraction (XRD) measurements over the voltage range 4.6–1.5 V. At 1.5 V, however, possible additional phases might have been present but not detectable due to their low concentration and/or their X‐ray amorphousness. The maximum valence state of the transition metal ions of +4 was reached in rhombohedral at 4.6 V where about per formula units remained on the lithium layers. Such a high lithium concentration between the slabs (M = metal ion on 3b layer sites) prevented the phase from developing a unit cell with the extremely small c axis parameter found for “” and and is believed to be an important prerequisite for the good cycle stability of between 4.8–2.5 V.

On the α(Al)/ δ′(Al 3Li) metastable solvus in aluminium–lithium alloys

Data for the α/ δ′(Al 3Li) solvus reported in the literature shows an extremely wide scatter. An attempt has therefore been made to redefine this solvus boundary using electrical resistivity measurements for low lithium concentrations and differential scanning calorimetry for high lithium concentrations. The concentration, C e, at the α/ δ′ boundary is closely defined over the range 2–13 at.% Li by the equation lnC e ( at.%)=4.176− 9180 RT and found to be in good agreement with values calculated from thermodynamic data. Zirconium additions of up to 0.05 at.% do not affect the position of the α/ δ′ boundary. A by-product of the investigation was the resistivity of the δ′(Al 3Li) phase, which was calculated to be 41 nΩm.

Synthesis and characterization of a new lithium-rich graphite intercalation compound: Li2C6Oy (y≈0.5)

The electrochemical reduction of the blue, second-stage NaC6O0.5 graphite intercalation compound (GIC) in LiClO4–ethylene carbonate electrolyte results in the formation of the new yellow quasi-stage 1 GIC, of biintercalation type and ideally formulated as Li2C6O0.5. Such a high lithium concentration has never been observed in GICs synthesized in ambient conditions. The identity period along the c axis is equal to 1035 pm and results, as in biintercalation compounds, in the addition of two interplanar spacings of different values: one equal to 370 pm as in LiC6 and the other equal to 665 pm, resulting from the intercalation of five alternating layers, three of lithium and two of oxygen. Sodium is present in this material in the form of regularly distributed metallic clusters.

Electron Microscopy Investigation of the Cycling-Induced Phase Transformation in LiMnO2 Compounds

ABSTRACTLithium transition metal oxides used as intercalation electrodes for rechargeable lithium batteries are widely studied in search of structural stability and improved electrochemical performance. Recent studies showed that the orthorhombic and monoclinic LiMnO2 compounds, unlike LiMn204 spinels, could be cycled on both the 4 V and 2.9 V plateaus with high and stable discharge capacity. In this study, we have performed direct high resolution observations of electrochemically cycled LiMnO2 particles in the fully discharged state. Extensive damage including local strain variation, nanodomain formation, and changes in cation ordering, has been observed. Individual particles retain overall single crystallinity despite having differing structures at the nanodomain level. While cycling causes a macroscopic transformation to spinel cation ordering, the formation of nanodomains differing in cation ordering and/or composition appears to accommodate or prevent the destructive Jahn-Teller distortion that normally occurs at high lithium concentration, thereby resulting in cycling stability.

Morphological characteristics of low density and high lithium content Li xNi 1 − xO cathodes for molten carbonate fuel cells

Li x Ni 1 − x O cathode structures were prepared by solid state reaction in air of nickel and lithium carbonate powder mixtures. Density changes of Ni Li 2 CO 3 composites following thermal treatment at 700 °C were determined as a function of starting composition and isothermal time so as to evaluate the effect of Li 2CO 3 content in the starting mixture on the microstructure of the resulting Li x Ni 1 − x O solid solutions. Total porosity, calculated from density data, increased up to the composition with 23 at% Li +, beyond which the porosity was nearly constant. An analysis of the compositions with nominal 30 and 44 at% Li + showed that, by Li 2CO 3 decomposition during isothermal treatment at 700 °C, both the amount and lithium atomic fraction of Li x Ni 1 − x O solid solution increased with time, but the porosity of the solid solution was unchanged. It was denoted that lithium carbonate affects lithium nickel oxide porosity by mass-to-void transformation during the reaction of Li 2CO 3 with Li y Ni 1 − y O to get Li x Ni 1 − x O with x > y, and by carbon oxide and/or carbon dioxide evolution following Li 2CO 3 decomposition. While the specific pore volume related to mass-to-void transformation increased with Li 2CO 3 amount, for high lithium content solid solutions, the specific pore volume, due to gas evolution, decreased with lithium carbonate content of the mixture.

Structural and Local Environment Modifications in a Chemically Lithiated Iron Thiospinel

We present a combined57Fe Mössbauer/X-ray diffraction (Rietveld analysis) study carried out on an In16Fe8S32spinel before and after chemical lithium insertion. To accommodate the new inserted cations in the structure, two mechanisms are observed. First, for a low lithium content, a cation migration takes place from the usually occupied 8aand 16dsites toward the usually unoccupied 8band 16csites, with distortion of the sulfur coordination polyhedra. Second, for a high lithium content, when both 16cand 16doctahedral sites are occupied, a decrease of the distortion of the polyhedra is observed. During the insertion process, no clear reduction of Fe atoms is observed but there is an increase in the covalent character of the Fe–S bonds.

Incorporation of lithium in single crystal diamond: diffusion profiles and optical and electrical properties

Abstract Doping of diamond by in-diffusion of lithium in natural type Ia and IIa single crystal diamond plates has been investigated. The lithium incorporation was realized by direct in-diffusion from a Li2O source at temperatures between 400 and 650 °C. Using secondary ion mass spectroscopy (SIMS) depth profiling, high concentrations of lithium, up to a level of 8.0 × 1021 cm−3 and gradually decreasing to 1.0 × 1019 cm−3 at a depth of 0.5 μm below the surface, were measured. From these profiles the diffusion constant of lithium in diamond was determined to be DLi(T) = 2 × 10−10exp (−0.9 eV/kT) cm2s−1. The the activation energy for diffusion of 0.9 ± 0.3 eV is in agreement with the theoretical literature value of 0.85 eV. Cathodoluminescence spectroscopy showed that the blue band-A luminescence, which is characteristic for natural type IIa diamond, is largely quenched by the presence of lithium. A shift of the maximum luminescence intensity towards higher energy values has been found. From photothermal deflection spectroscopy and optical transmission measurements no new optically active defect is observed after lithium in-diffusion. However, these measurements indicated the occurrence of a large concentration of light scattering centres, the size of which is 10 nm or less. This suggests that lithium is clustered in the crystal volume just below the specimen surface and therefore is not electrically active.

Structure and Dynamics of Lithium-Intercalated SnS2. 6,7Li and 119Sn Solid State NMR

Lithium-intercalated SnS2 compounds have been studied with 6,7Li and 119Sn solid state NMR spectroscopy addressing the location of the insertion sites of the lithium. The central transition in the 7Li NMR spectra can be decomposed into two components giving rise to different quadrupole coupling constants and may be assigned to lithium in octahedral and tetrahedral lattice sites. 1H and 7Li decoupling experiments with 6Li NMR detection as well as the narrowing effect of magic angle spinning on the 7Li NMR line width indicate the presence of dipolar interactions. Temperature dependent 7Li NMR spin−lattice relaxation times reveal a decrease in activation energy for lithium motion at higher lithium contents. 119Sn spectra revealed additional peaks shifted downfield from the Sn(IV) resonance. 119Sn spin−lattice relaxation times and the total number of observable tin nuclei indicate that with increasing lithium content interactions with delocalized electrons may be present. In summary, the NMR results show that...

Theoretical studies of the electronic structures and linear, nonlinear optics of K 3− xLi 2+ xNb 5O 15 with x = 0 and x = 1

The electronic structures of the ground state have been calculated using the INDO/1-SCI method, and in combination with the sum-over-states method, the first and second frequency dependent polarizabilities have been obtained for microscopic species of K 3− x Li 2+ x Nb 5O 15 with x = 0 and x = 1. The calculated birefringences δn and phase matching nonlinear optical coefficients d 31 indicate that the K 3− x Li 2+ x Nb 5O 15 with higher lithium content will enhance nonlinear optical effects at the fundamental wavelengths of 1064 and 820 nm. The charge transfer states formed from oxygen atomic 2p orbitals with a mixing of niobium atomic 4d character to alkali metal atomic valence orbitals with mixing of niobium 5s, 5p character make the most significant contributions to the susceptibility.

An investigation of high lithium concentrations

The circumstances associated with high lithium concentrations detected by 23 district laboratories in the West Midlands during a 22 month period were investigated.

Effects of lithium intercalation on the electronic properties of FePS3 single crystals.

The reaction of FePS3 single crystals with a 1.6M n-butyl lithium solution in n-hexane has been followed through de electrical conductivity measurements as a function of the intercalation time. In order to investigate the influence of lithium insertion on the FePS3 electronic properties we have also measured as a function of both temperature and intercalation time the de conductivity of equilibrated LixFePS3 single crystals. Upon lithium intercalation we have observed the following main effects: (i) an increase in the electrical conductivity, (ii) a simultaneous decrease in the activation energy, and (iii) a degenerate semiconductor behavior at the highest lithium content. In analogy to the LixNiPS3 systems, these results, discussed in terms of both the rigid band model and the so-called transition-metal weakly interacting one, seem to indicate that in the LixFePS3 complexes a new conduction mechanism appears at a different energy level from the beginning of the intercalation process with respect to the pure FePS3. Aiming at a better understanding of the still uncertain nature of reduction sites in the FePS3 lattice during lithium intercalation, we have also carried out Fourier transform infrared absorption measurements on single crystals of FePS3 and their lithium intercalation compounds at room temperature and in the frequency region from 800 to 3000 cm(-1). The results agree well with both the literature and the above conductivity data allowing a better identification of the lithium 2s electron accepting levels.

Effect of lithium addition upon γ-Al2O3 for isopropanol dehydration

The effect of lithium addition to γ-Al 2 O 3 on the acidity and on the catalytic behaviour in the isopropanol dehydration reaction is studied. Results show that there is an important blocking or poisoning effect of lithium on the Lewis Al 3+ sites of the alumina surface ; these sites play an important role in the isopropanol dehydration reaction to di-isopropylether and propylene. The di-isopropylether formation is drastically reduced by lithium addition, while the propylene formation can be maintained, even at a high lithium content, by increasing the reaction temperature. Results are interpreted by considering that the ether would be produced by a concerted mechanism (E 2 ), and the olefin formation could be carried out by both E 2 or E 1 mechanisms.

Electroacoustic Study of Adsorption of Ions on Anatase and Zirconia from Very Concentrated Electrolytes

The reduction of absolute values of negative ζ potentials (basic branch) of anatase with the concentration of 1−1 salts (alkali halides, nitrates, and perchlorates) is much more pronounced than that of the positive ζ potentials (acidic branch). The extent of this effect increases in the series Cs < K < Na < Li for a given anion and CH3COO < Cl < NO3 < ClO4 < Br < I for a given cation. For sufficiently high concentrations of most lithium and sodium salts, e.g., 0.53 mol dm-3 NaI, there is no isoelectric point (iep) and the ζ potentials are positive over the entire available pH range. For potassium and cesium salts, an iep is always observed, even at very high concentrations, but it is substantially shifted toward the higher pH values. Small cations show a differentiating effect: the course of ζ(pH) curves for particular lithium and sodium salts at a given high ionic strength is very sensitive to the nature of the anion, but the effect of the nature of the anion is relatively insignificant when different potassium salts are considered. Large anions (iodide) show a differentiating effect, while smaller anions (chloride) do not.

1234 Localization of mRNA for leukemia inhibitory factor receptor in the rat brain

Serotonin (5-HT)- or thrombin-stimulated platelet intracellular calcium (Ca) mobilization has been reported to be enhanced in patients with bipolar disorders. However, the mechanism of this enhancement is unknown. As a preliminary study, the authors examined the effects of a myosin light chain kinase (MLCK) inhibitor, 1-(5-chloronaphthalene-1-sulfonyl)-1H-hexahydro-1,4-diazepine hydrochloride (ML-9), and two drugs that are mainstays of treatment for bipolar disorder, lithium and valproate, on 5-HT- or thrombin-induced Ca increase in the platelets of normal subjects. When preincubated with 30 μM ML-9, Ca responses to both agonists were enhanced. Valproate showed a dose-dependent attenuation of agonist-induced intracellular Ca rise, both in the absence and presence of ML-9. Although lithium alone had no significant effect on the Ca increase, a high concentration of lithium significantly decreased Ca mobilization only in the presence of ML-9. These results suggest that the enhanced Ca response observed in bipolar disorder might be relevant to decreased function of MLCK and that the mechanism of action of lithium may include a compensatory effect on MLCK modulation.

Studies on LiMnO spinel system (obtained from melt-impregnation method) as a cathode for 4 V lithium batteries Part II. Optimum spinel from γ-MnOOH

The mechanism for the formation of a spinel compound from the reaction of LiNO 3 with a high density γ-MnOOH is extensively investigated in terms of pore-size distribution, X-ray diffraction, thermal and chemical analyses. The reaction of MnOOH with LiNO 3 at about 300°C yields a product that consists of domains of lithiated MnO 2 phase with an approximate composition of Li 0.3MnO 2. This product ultimately transforms to a disordered spinel phase of composition LiMn 2O 4 + y at 300–400°C. The disordered spinel is converted to a well-ordered as the temperature is raised above 550°C. The oxygen content depends on the final heating temperature and atmosphere. Compounds obtained at high temperature, or in N 2, have a large capacity and unstable rechargeability. By contrast, some compounds prepared at low temperature, or with a slightly high lithium content in the starting materials, exhibit an improvement in rechargeability. The possible cause for the differences in electrochemical characteristics of both types of compound is proposed.