Collisional-radiative study of lithium plasmas

The sensitivity of lithium plasma models to the underlying atomic data is investigated. Collisional-radiative modeling is carried out with both the Los Alamos and ADAS suite of codes. The effects of plane-wave Born, distorted-wave, and nonperturbative R -matrix with pseudostates and time-dependent close-coupling electron impact atomic data on derived plasma quantities such as the ionization balance and radiated power are studied. Density and temperature regimes are identified where nonperturbative excitation and ionization rate coefficients must be used. The electron temperature and density ranges investigated were 0.2 eV<or = T(e) <or =90 eV and 10(10) cm(-3) <or = N(e) <or = 10(14) cm(-3).

Development of lithium disilicate based glass-ceramics

O principal objectivo deste estudo foi o desenvolvimento de vitrocerâmicos à base de dissilicato de lítio no sistema Li2O-K2O-Al2O3-SiO2 contendo uma razão molar SiO2/Li2O muito afastada da do dissilicato de lítio (Li2Si2O5) usando composições simples e a técnica tradicional de fusão-vazamento de vidro de forma a obter materiais com propriedades mecânicas, térmicas, químicas e eléctricas superiores que permitam a utilização destes materiais em diversas aplicações funcionais. Investigou-se o fenómeno de separação de fases, a cristalização e as relações estrutura-propriedades de vidros nos sistemas Li2O-SiO2, Li2O-Al2O3-SiO2 e Li2O-K2O-Al2O3-SiO2. Os vidros nos sistemas Li2O-SiO2 e Li2O-Al2O3-SiO2 apresentaram fraca densificação e resultaram em materiais frágeis, contrastando com a boa sinterização dos vidros no sistema Li2O-K2O-Al2O3-SiO2. Pequenas adições de Al2O3 e K2O ao sistema Li2O-SiO2 permitiram controlar a separação de fases devido à formação de espécies de Al(IV) que confirmaram o papel de Al2O3 como formador de rede. Os compactos de pó de vidro das composições contendo Al2O3 e K2O tratados termicamente resultaram em vitrocerâmicos bem densificados, apresentando dissilicato de lítio como a principal fase cristalina, e valores de resistência mecânica à flexão, resistência química e condutividade eléctrica (173-224 MPa, 25-50 mg/cm2 e ~2´10-18 S/cm, respectivamente) que possibilitam a utilização destes materiais em diversas aplicações funcionais. A adição de P2O5, TiO2 e ZrO2 ao sistema Li2O-K2O-Al2O3-SiO2 como agentes nucleantes revelou que os vidros contendo apresentaram cristalização em volume, com a formação de metassilicato de lítio a temperaturas mais baixas e dissilicato de lítio para as temperaturas mais elevadas, enquanto a adição de zircónia reduz o grau de segregação, aumenta a polimerização da matriz vítrea e desloca o valor de Tg para temperaturas superiores, inibindo a cristalização.

Genome-wide Association Study Identifies SESTD1 as a Novel Risk Gene for Lithium Responsive Bipolar Disorder

Lithium is the mainstay prophylactic treatment for bipolar disorder (BD), but treatment response varies considerably across individuals. Patients who respond well to lithium treatment might represent a relatively homogeneous subtype of this genetically and phenotypically diverse disorder. Here, we performed genome-wide association studies (GWAS) to identify (i) specific genetic variations influencing lithium response and (ii) genetic variants associated with risk for lithium-responsive BD. Patients with BD and controls were recruited from Sweden and the United Kingdom. GWAS were performed on 2698 patients with subjectively defined (self-reported) lithium response and 1176 patients with objectively defined (clinically documented) lithium response. We next conducted GWAS comparing lithium responders with healthy controls (1639 subjective responders and 8899 controls; 323 objective responders and 6684 controls). Meta-analyses of Swedish and UK results revealed no significant associations with lithium response within the bipolar subjects. However, when comparing lithium-responsive patients with controls, two imputed markers attained genome-wide significant associations, among which one was validated in confirmatory genotyping (rs116323614, P=2.74 × 10-8). It is an intronic single-nucleotide polymorphism (SNP) on chromosome 2q31.2 in the gene SEC14 and spectrin domains 1 (SESTD1), which encodes a protein involved in regulation of phospholipids. Phospholipids have been strongly implicated as lithium treatment targets. Furthermore, we estimated the proportion of variance for lithium-responsive BD explained by common variants ('SNP heritability') as 0.25 and 0.29 using two definitions of lithium response. Our results revealed a genetic variant in SESTD1 associated with risk for lithium-responsive BD, suggesting that the understanding of BD etiology could be furthered by focusing on this subtype of BD.

Temporal changes in mRNA expression of the brain nutrient transporters in the lithium-pilocarpine model of epilepsy in the immature and adult rat.

The lithium-pilocarpine model mimics most features of human temporal lobe epilepsy. Following our prior studies of cerebral metabolic changes, here we explored the expression of transporters for glucose (GLUT1 and GLUT3) and monocarboxylates (MCT1 and MCT2) during and after status epilepticus (SE) induced by lithium-pilocarpine in PN10, PN21, and adult rats. In situ hybridization was used to study the expression of transporter mRNAs during the acute phase (1, 4, 12 and 24h of SE), the latent phase, and the early and late chronic phases. During SE, GLUT1 expression was increased throughout the brain between 1 and 12h of SE, more strongly in adult rats; GLUT3 increased only transiently, at 1 and 4h of SE and mainly in PN10 rats; MCT1 was increased at all ages but 5-10-fold more in adult than in immature rats; MCT2 expression increased mainly in adult rats. At all ages, MCT1 and MCT2 up-regulation was limited to the circuit of seizures while GLUT1 and GLUT3 changes were more widespread. During the latent and chronic phases, the expression of nutrient transporters was normal in PN10 rats. In PN21 rats, GLUT1 was up-regulated in all brain regions. In contrast, in adult rats GLUT1 expression was down-regulated in the piriform cortex, hilus and CA1 as a result of extensive neuronal death. The changes in nutrient transporter expression reported here further support previous findings in other experimental models demonstrating rapid transcriptional responses to marked changes in cerebral energetic/glucose demand.

alphaENaC-mediated lithium absorption promotes nephrogenic diabetes insipidus.

Lithium-induced nephrogenic diabetes insipidus (NDI) is accompanied by polyuria, downregulation of aquaporin 2 (AQP2), and cellular remodeling of the collecting duct (CD). The amiloride-sensitive epithelial sodium channel (ENaC) is a likely candidate for lithium entry. Here, we subjected transgenic mice lacking αENaC specifically in the CD (knockout [KO] mice) and littermate controls to chronic lithium treatment. In contrast to control mice, KO mice did not markedly increase their water intake. Furthermore, KO mice did not demonstrate the polyuria and reduction in urine osmolality induced by lithium treatment in the control mice. Lithium treatment reduced AQP2 protein levels in the cortex/outer medulla and inner medulla (IM) of control mice but only partially reduced AQP2 levels in the IM of KO mice. Furthermore, lithium induced expression of H(+)-ATPase in the IM of control mice but not KO mice. In conclusion, the absence of functional ENaC in the CD protects mice from lithium-induced NDI. These data support the hypothesis that ENaC-mediated lithium entry into the CD principal cells contributes to the pathogenesis of lithium-induced NDI.

A G. C./M. S. study of the reaction and decomposition products of pentafluorophenyl-grignard and lithium reagents

Decomposition and side reactions of, and the synthetic use of, pentafluorophenylmagnesium bromide and pentafluorophenyllithium have been investigated using G,C9/M.S, techniques• Their reactions with reagents such as CgF^X (X - H, F, CI, Br, 1), C6F4X2 (X - H, CI)f C6F3C13, C6H6. (CgX5)3P (X = H, F), (C6X5)3P=0 (X = H, F), (CgX5)Si (CH3)3 (X = H, F) and (CH0K SiCl , n = 1,2, in ether or ether/n-hexane were studied• In addition to the principal reaction of synthetic use, namely the replacement of a halogen by a pentafluorophenyl group, two types of side reactions were observed* These were (i) intermolecular loss of LiF via a nucleophilic substitution, and (ii) intramolecular loss of LiF, followed by the addition of either inorganic salts such as lithium or magnesium halides, or organometal compounds such as organolithium or organo-Grigaard* G.C«/M.S. techniques were routinely employed to study complicated reaction mixtures. Although mass spectrometry alone has disadvantages for the identification of isomers, deduction of the most probable pathway often helps overcome this problem.

Novel approaches to the synthesis and treatment of cathode materials for lithium-ion batteries

Nous avons mis au point une approche novatrice pour la synthèse d’un matériau de cathode pour les piles lithium-ion basée sur la décomposition thermique de l’urée. Les hydroxydes de métal mixte (NixMnxCo(1-2x)(OH)2) ont été préparés (x = 0.00 à 0.50) et subséquemment utilisés comme précurseurs à la préparation de l’oxyde de métal mixte (LiNixMnxCo(1-2x)O2). Ces matériaux, ainsi que le phosphate de fer lithié (LiFePO4), sont pressentis comme matériaux de cathode commerciaux pour la prochaine génération de piles lithium-ion. Nous avons également développé un nouveau traitement post-synthèse afin d’améliorer la morphologie des hydroxydes. L’originalité de l’approche basée sur la décomposition thermique de l’urée réside dans l’utilisation inédite des hydroxydes comme précurseurs à la préparation d’oxydes de lithium mixtes par l’intermédiaire d’une technique de précipitation uniforme. De plus, nous proposons de nouvelles techniques de traitement s’adressant aux méthodes de synthèses traditionnelles. Les résultats obtenus par ces deux méthodes sont résumés dans deux articles soumis à des revues scientifiques. Tous les matériaux produits lors de cette recherche ont été analysés par diffraction des rayons X (DRX), microscope électronique à balayage (MEB), analyse thermique gravimétrique (ATG) et ont été caractérisés électrochimiquement. La performance électrochimique (nombre de cycles vs capacité) des matériaux de cathode a été conduite en mode galvanostatique.

A detailed study of the lithiation of iron phosphate as well as the development of a novel synthesis of lithium iron silicate as cathode material for lithium-ion batteries

Dans cette thèse nous démontrons le travail fait sur deux matériaux de cathodes pour les piles lithium-ion. Dans la première partie, nous avons préparé du phosphate de fer lithié (LiFePO4) par deux méthodes de lithiation présentées dans la littérature qui utilisent du phosphate de fer (FePO4) amorphe comme précurseur. Pour les deux méthodes, le produit obtenu à chaque étape de la synthèse a été analysé par la spectroscopie Mössbauer ainsi que par diffraction des rayons X (DRX) pour mieux comprendre le mécanisme de la réaction. Les résultats de ces analyses ont été publiés dans Journal of Power Sources. Le deuxième matériau de cathode qui a été étudié est le silicate de fer lithié (Li2FeSiO4). Une nouvelle méthode de synthèse a été développée pour obtenir le silicate de fer lithié en utilisant des produits chimiques peu couteux ainsi que de l’équipement de laboratoire de base. Le matériau a été obtenu par une synthèse à l’état solide. Les performances électrochimiques ont été obtenues après une étape de broyage et un dépôt d’une couche de carbone. Un essai a été fait pour synthétiser une version substituée du silicate de fer lithié dans le but d’augmenter les performances électrochimiques de ce matériau.

Low cost synthesis of cathode and anode materials for lithium-ion batteries

Dans cette thèse, nous démontrons des travaux sur la synthèse à faible coût des matériaux de cathode et l'anode pour les piles lithium-ion. Pour les cathodes, nous avons utilisé des précurseurs à faible coût pour préparer LiFePO4 et LiFe0.3Mn0.7PO4 en utilisant une méthode hydrothermale. Tout d'abord, des matériaux composites (LiFePO4/C) ont été synthétisés à partir d'un précurseur de Fe2O3 par une procédé hydrothermique pour faire LiFePO4(OH) dans une première étape suivie d'une calcination rapide pour le revêtement de carbone. Deuxièmement, LiFePO4 avec une bonne cristallinité et une grande pureté a été synthétisé en une seule étape, avec Fe2O3 par voie hydrothermale. Troisièmement, LiFe0.3Mn0.7PO4 a été préparé en utilisant Fe2O3 et MnO comme des précurseurs de bas coûts au sein d'une méthode hydrothermale synthétique. Pour les matériaux d'anode, nous avons nos efforts concentré sur un matériau d'anode à faible coût α-Fe2O3 avec deux types de synthèse hydrothermales, une a base de micro-ondes (MAH) l’autre plus conventionnelles (CH). La nouveauté de cette thèse est que pour la première fois le LiFePO4 a été préparé par une méthode hydrothermale en utilisant un précurseur Fe3+ (Fe2O3). Le Fe2O3 est un précurseur à faible coût et en combinant ses coûts avec les conditions de synthèse à basse température nous avons réalisé une réduction considérable des coûts de production pour le LiFePO4, menant ainsi à une meilleure commercialisation du LiFePO4 comme matériaux de cathode dans les piles lithium-ion. Par cette méthode de préparation, le LiFePO4/C procure une capacité de décharge et une stabilité de cycle accrue par rapport une synthétisation par la méthode à l'état solide pour les mêmes précurseurs Les résultats sont résumés dans deux articles qui ont été récemment soumis dans des revues scientifiques.

The Steady-State and Transient Characteristic Analysis of Thermal Fixing a Photorefractive Hologram Grating in Lithium Niobate

The transient interaction between a refraction index grating and light beams during simultaneous writing and thermal fixing of a photorefractive hologram is investigated. With a diffusion- and photovoltaic-dominated carrier transport mechanism and carrier thermal activation (temperature dependent) considered in Fe:LiNbO3 crystal, from the standpoint of field-material coupling, the theoretical thermal fixing time and the space-charge field buildup, spatial distribution, and temperature dependence are given numerically by combining the band transport model with mobile ions with the coupled-wave equation

Phase transitions in lithium ammonium sulfate below room temperature: An ultrasonic study

A detailed ultrasonic study of the elastic properties of lithium ammonium sulfate ~LiNH4SO4! or LAS has been carried out below room temperature. The elastic constants of LAS at room temperature are reported. The discrepancy present in earlier elastic constant data associated with the different choice of axes for this orthorhombic system are clarified. The results of the temperature variation study down to 220 K confirm the ferroelastic phase transition at 285 K and establish a thermal hysteresis of about 2.5 K between the cooling and heating cycles. Results of the investigation on the suspected weak phase transition at 256 K suggest that this transition occurs at 242 K on cooling and at 256 K on heating, thus having a thermal hysteresis of about 14 K. However, since the observed elastic anomaly for this transition is very small, the nature of this transition still remains unclear

Anisotropy in elastic properties of lithium sodium sulphate hexahydrate single crystal—An ultrasonic study

The double sulfate family (ABSO4), where A and B are alkali metal cations, is the object of great interest owing to the complexity and richness of its sequence of phase transition induced by temperature variation. A new sulfate salt characterized by the presence of water molecule in the unit cell with the chemical formula, Li2Na3(SO4)2⋅6H2O (LSSW), was obtained. The ultrasonic velocity measurement was done with pulse echo overlap technique [PEO]. All the six second order elastic stiffness constants, C11 = C22, C33, C44 = C55, C12, C14 and C13 = C23 are reported for the first time. The anisotropy in the elastic properties of the crystal are well explained by the pictorial representation of the polar plots of phase velocity, slowness, Young’s modulus and linear compressibility in a–b and a–c planes.

Lithium Containing Complex Metal Oxides and Metal phosphates:Investigations on their synthesis and various characterizations for rechargeable lithium battery applications

The work presented in the thesis is centered around two important types of cathode materials, the spinel structured LixMn204 (x =0.8to1.2) and the phospho -oIivine structured LiMP04 (M=Fe and Ni). The spinel system LixMn204, especially LiMn204 corresponding to x= 1 has been extensively investigated to understand its structural electrical and electrochemical properties and to analyse its suitability as a cathode material in rechargeable lithium batteries. However there is no reported work on the thermal and optical properties of this important cathode material. Thermal diffusivity is an important parameter as far as the operation of a rechargeable battery is concerned. In LixMn204, the electronic structure and phenomenon of Jahn-Teller distortion have already been established theoretically and experimentally. Part of the present work is an attempt to use the non-destructive technique (NDT) of photoacoustic spectroscopy to investigate the nature of the various electronic transitions and to unravel the mechanisms leading to the phenomenon of J.T distortion in LixMn204.The phospho-olivines LiMP04 (M=Fe, Ni, Mn, Co etc) are the newly identified, prospective cathode materials offering extremely high stability, quite high theoretical specific capacity, very good cycIability and long life. Inspite of all these advantages, most of the phospho - olivines especially LiFeP04 and LiNiP04 show poor electronic conductivity compared to LixMn204, leading to low rate capacity and energy density. In the present work attempts have been made to improve the electronic conductivity of LiFeP04 and LiNiP04 by adding different weight percentage MWNT .It is expected that the addition of MWNT will enhance the electronic conductivity of LiFeP04 and LiNiP04 with out causing any significant structural distortions, which is important in the working of the lithium ion battery.

Structural, electrical and electrochemical characterization of high frequency magnetron sputtered spinel oxide cathode films for lithium ion battery applications

The main challenges in the deposition of cathode materials in thin film form are the reproduction of stoichiometry close to the bulk material and attaining higher rates of deposition and excellent crystallinity at comparatively lower annealing temperatures. There are several methods available to develop stoichiometric thin film cathode materials including pulsed laser deposition; plasma enhanced chemical vapor deposition, electron beam evaporation, electrostatic spray deposition and RF magnetron sputtering. Among them the most versatile method is the sputtering technique, owing to its suitability for micro-fabricating the thin film batteries directly on chips in any shape or size, and on flexible substrates, with good capacity and cycle life. The main drawback of the conventional sputtering technique using RF frequency of 13.56MHz is its lower rate of deposition, compared to other deposition techniques A typical cathode layer for a thin film battery requires a thickness around one micron. To deposit such thick layers using convention RF sputtering, longer time of deposition is required, since the deposition rate is very low, which is typically 10-20 Å/min. This makes the conventional RF sputtering technique a less viable option for mass production in an economical way. There exists a host of theoretical and experimental evidences and results that higher excitation frequency can be efficiently used to deposit good quality films at higher deposition rates with glow discharge plasma. The effect of frequencies higher than the conventional one (13.56MHz) on the RF magnetron sputtering process has not been subjected to detailed investigations. Attempts have been made in the present work, to sputter deposit spinel oxide cathode films, using high frequency RF excitation source. Most importantly, the major challenge faced by the thin film battery based on the LiMn2O4 cathode material is the poor capacity retention during charge discharge cycling. The major causes for the capacity fading reported in LiMn2O4cathode materials are due to, Jahn-Teller distortion, Mn2+ dissolution into the electrolyte and oxygen loss in cathode material during cycling. The work discussed in this thesis is an attempt on overcoming the above said challenges and developing a high capacity thin film cathode material.