Viabilidad técnica para la explotación y separación isotópica de Li y prospectiva en el mercado de baterías de ION-7Li y de 6Li como material base de diseño en reactores de fusión nuclear

En claro alineamiento con estrategias de sostenibilidad en el uso de recursos naturales en un escenario constante de aumento de la demanda energética mundial, el desarrollo de la tecnología energética en la Historia de la Especie Humana muestra un vector de evolución permanente desde su origen en el sentido del desarrollo y uso de nuevas fuentes energéticas con la explotación de recursos naturales de manera más eficiente: soluciones energéticas con aumento de la densidad energética (exoenergía de proceso por unidad de masa de recurso natural). Así el cambio de escala en la demanda de explotación del Litio como recurso natural se viene presentando en la última década ligada al desarrollo del mercado de las baterías "ion-Litio" y los requisitos de combustible (Deuterio y Litio) en el camino de la fusión nuclear como opción energética próxima. El análisis anticipado de las demandas sinérgicas a escala de ambos mercados aparece de enorme interés prospectivo en sus aspectos técnicos: (1) tecnologías de base para la extracción mineral y de agua marina y (2) su enriquecimiento isotópico (de interés sinérgico; 7Li para baterías eficientes ion-litio; 6Li como regenerador de tritio en ciclo de combustible en fusión nuclear) a la vez que en sus aspectos económicos. Este Proyecto realiza: (1) un ejercicio de análisis prospectivo de la demanda y de mercado para el enriquecimiento 6Li/7Li para las próximas décadas, (2) se califican los desarrollos tecnológicos específicos que van a poder permitir la producción a escala conforme a la demanda; (3) se selecciona y califica una técnica [de centrifugación / termo-difusión/ destilación combinada] como opción tecnológicamente viable para la producción a escala de formas litiadas; (4) se propone un diseño conceptual de planta de producción y finalmente (5) propone un estudio de viabilidad para la demostración de proceso y construcción de dicha planta de demostración de la nueva capacidad tecnológica. ABSTRACT Clearly aligned with sustainability strategies under growing world energy demand in the use of natural resources the development of energy technology in the history of the human species shows a vector of ongoing evolution from its origin in the sense of the development and use of new energy sources with the exploitation of natural resources in a more efficient manner. The change of scale in the demand for exploitation of Lithium as a natural resource appears during the last decade as bound to the deployment of "lithium-ion" batteries market and to the Nuclear Fusion fuels (deuterium and lithium) supply scaled demands. The prospective analysis of demands to scale in both markets appears in scene with huge prospective interest in its technical aspects: (1) base technologies for mineral and water marine extraction (2) its isotopic enrichment (synergistic interests; 7Li efficient battery Li-ion; 6Li as fusion nuclear fuel breeder (tritium) as well as in its economic aspects. This Project: (1) propose a prospective analysis exercise of the synergistic supply demand for coming decades for the enrichment of 6Li and 7Li, (2) qualifies specific technological developments ongoing to respond to supply demand; (3) select and qualifies an appropriate technique [combined centrifugation/thermo-diffusion/distillation] as technologically viable option for lithiated forms scaled-production; (4) proposes a conceptual design of production plant based on the technique and finally (5) proposes a feasibility study for the process demonstration and construction of this new technological capability Demonstration Plant.

Síntesis, caracterización, propiedades eléctricas y electroquímicas de Na₃V₂-xAlx(PO₄)2F₃ (x=0,0.02, 0.05, 0.1) como cátodos para su aplicación en baterías de ion-litio

Propósito y Método del Estudio: La demanda de baterías recargables ha aumentado de manera significativa cada año durante la última década impulsada por las necesidades vinculadas con el desarrollo tecnológico (portabilidad, alto desempeño de dispositivos electrónicos, vehículos eléctricos). La batería ión-litio es el dispositivo de mayor consumo, está diseñado para el almacenamiento y conversión de energía eléctrica basado en electrodos de intercalación. En la actualidad los esfuerzos están dirigidos a la mejora y/o remplazo de los componentes actuales de las baterías: ánodo, cátodo (LiCoO2) y electrolito, por materiales que tengan más altos rendimientos en términos de energía, potencia, costo, confiabilidad, tiempo de vida y seguridad. En este trabajo de investigación se prepararon y caracterizaron cuatro compuestos Na3V2-xAlx(PO4)2F3 (x= 0, 0.02, 0.05, 0.1) como materiales catódicos para baterías ión-litio. Estos materiales se obtuvieron mediante el método Pechini. La caracterización morfológica y microestructural se llevó a cabo por Microscopia Electrónica de Barrido de Emisión de Campo (FESEM), el análisis textural por Fisisorción de N2 por la técnica BET; la composición química y cristalográfica se determinó por Espectroscopia de Emisión de Plasma de Acoplamiento Inductivo (ICP-OES), Espectroscopia de Energía Dispersiva de Rayos X (EDXS) y Difracción de Rayos X (XRD), mientras que por Espectroscopia de Impedancia Electroquímica (EIS) se realizó la caracterización eléctrica; por último la aplicación de los materiales como cátodos en baterías ión-litio se evaluó mediante pruebas Galvanostáticas de carga/descarga. Contribuciones y Conclusiones: Se establecieron las condiciones de síntesis para los materiales Na3V2-xAlx(PO4)2F3 x= 0, 0.02, 0.05 y 0.1 vía método Pechini. El dopaje de la fase Na3V2-xAlx(PO4)2F3 se llevó a cabo con éxito hasta x=0.1 moles de aluminio, dado que se conservó la estructura cristalina tetragonal del Na3V2(PO4)2F3 (JCPDS 01-089-8485). Los materiales obtenidos tienen una microestructura formada por partículas de forma granular de tamaño nanométrico (40-100nm), esto se atribuye al efecto del carbono residual en la muestra (en promedio 8% en peso) ya que inhibe el crecimiento de partícula, además que permite mejorar el contacto entre las partículas lo que beneficia a la conductividad electrónica del material. Los materiales obtenidos tienen en promedio un tamaño de poro de 20 nm, con un área superficial del orden 30 m2/g. La fase con 0.05 moles de aluminio presentó el mejor resultado bajo las condiciones de estudio. Conjuga dos de las características básicas de una batería, presenta una alta capacidad de carga/descarga (123/101 mAh/g a un voltaje de celda de 4.4 V vs Li) y una buena capacidad de retención (82%), en comparación al material sin dopar (128/63 mAh/g y 49% de retención). Por lo anterior, el dopaje de la fase Na3V2(PO4)2F3 con Al, logró la estabilización de la estructura frente a los procesos de ciclado. Por lo cual es un material prometedor para su aplicación como cátodos en baterías ión-litio o ión-sodio.

Effect of fiber orientation in gelled poly (vinylience fluoride) electrospun membranes for Li-ion battery applications

Battery separators based on electrospun membranes of poly(vinylidene fluoride) (PVDF) have been prepared in order to study the effect of fiber alignment on the performance and characteristics of the membrane. The prepared membranes show an average fiber diameter of ~272 nm and a degree of porosity of ~87 %. The gel polymer electrolytes are prepared by soaking the membranes in the electrolyte solution. The alignment of the fibers improves the mechanical properties for the electrospun membranes. Further, the microstructure of the membrane also plays an important role in the ionic conductivity, being higher for the random electrospun membrane due to the lower tortuosity value. Independently of the microstructure, both membranes show good electrochemical stability up to 5.0 V versus Li/Li+. These results show that electrospun membranes based on PVDF are appropriate for battery separators in lithium-ion battery applications, the random membranes showing a better overall performance.

Polyol-mediated synthesis of ultrafine tin oxide nanoparticles for reversible Li-ion storage

A simple, cheap and versatile, polyol-mediated fabrication method has been extended to the synthesis of tin oxide nanoparticles on a large scale. Ultrafine SnO2 nanoparticles with crystallite sizes of less than 5 nm were realized by refluxing SnCl2 . 2H(2)O in ethylene glycol at 195 degrees C for 4 h under vigorous stirring in air. The as-prepared SnO2 nanoparticles exhibited enhanced Li-ion storage capability and cyclability, demonstrating a specific capacity of 400 mAh g(-1) beyond 100 cycles. (c) 2006 Elsevier B.V. All rights reserved.

Hexagonal-shaped tin glycolate particles: A preliminary study of their suitability as li-ion insertion electrodes

Tin glycolate particles were prepared by a simple, one-step, polyol-mediated synthesis in air in which tin oxalate precursor was added to ethylene glycol and heated at reflux. Hexagonal-shaped, micron-sized tin glycolate particles were formed when the solution had cooled. A series of tin oxides was produced by calcination of the synthesized tin glycolate at 600-800 degrees C. It was revealed that the micron-sized, hexagonal-shaped tin glycolate now consisted of nanosized tin-based particles (80-120 nm), encapsulated within a tin glycolate shell. XRD, TGA, and FT-IR measurements were conducted to account for the three-dimensional growth of the tin glycolate particles. When applied as an anode material for Li-ion batteries, the synthesized tin glycolate particles showed good electro-chemical reactivity in Li-ion insertion/ deinsertion, retaining a specific capacity of 416mAhg(-1) beyond 50cycles. Ibis performance was significantly better than those of all the other tin oxides nanoparticles (< 160mAhg(-1)) obtained after heat treatment in air. We strongly believe that the buffering of the volume expansion by the glycolate upon Li-Sn alloying is the main factor for the improved cycling of the electrode.

Numerical modeling of the failure mechanisms in Si thin film anode for Li-ion batteries

In recent times, the demand for the storage of electrical energy has grown rapidly for both static applications and the portable electronics enforcing the substantial improvement in battery systems, and Li-ion batteries have been proven to have maximum energy storage density in all rechargeable batteries. However, major breakthroughs are required to consummate the requirement of higher energy density with lower cost to penetrate new markets. Graphite anode having limited capacity has become a bottle neck in the process of developing next generation batteries and can be replaced by higher capacity metals such as Silicon. In the present study we are focusing on the mechanical behavior of the Si-thin film anode under various operating conditions. A numerical model is developed to simulate the intercalation induced stress and the failure mechanism of the complex anode structure. Effect of the various physical phenomena such as diffusion induced stress, plasticity and the crack propagation are investigated to predict better performance parameters for improved design.

Faulted Structures in Li Ion Exchanged NaMO2 (M=Ni(0.25)Mn(0.75))

A family of LiMO2 materials (M=Ni0.25Mn0.75) was prepared from Na1.2-xLixMO∂ precursors (0≤x≤0.6) via ion exchange. The resulting IE products were examined via XRD and compared to simulated XRD patterns produced using DIFFax to determine the defect structures resulting from the IE process. For the 0.1≤x≤0.6 materials, it is observed that there are 3 LiMO2 sub-phases with different Li contents present. As the amount of Li in the precursor increases, the amount of each phase changes resulting in a net shift to higher 2-theta; corresponding to an overall decrease in lattice parameter, approaching the theoretical values for LiMO2. Additionally, as x increases, the probability of O3-type shifting increases, most likely due to an increase in the amount O3-Li2MO3 minority phase which acts to weaken bonds in the TM layer, allowing the O3 shift to occur more easily. For the x=0 IE product, it was seen that the product had an ~O2-type structure, but with lattice parameters closer to those expected for a NaMO2 material.

Li distribution characterization in Li-ion batteries positive electrodes containing LixNi0.8Co0.15Al0.05O2 secondary particles

The elemental distribution of as-received (non-charged) and charged Li-ion battery positive electrodes containing LixNi0.8Co0.15Al0.05O2 (0.75 ? x ? 1.0) microparticles as active material is characterized by combining μ-PIXE and μ-PIGE techniques. PIGE measurements evidence that the Li distribution is inhomogeneous (existence of Li-rich and Li-depleted regions) in as-received electrodes corresponding with the distribution of secondary particles but it is homogeneous within the studied individual secondary micro-particles. The dependence of the Li distribution on electrode thickness and on charging conditions is characterized by measuring the Li distribution maps in specifically fabricated cross-sectional samples. These data show that decreasing the electrode thickness down to 35 μm and charging the batteries at slow rate give rise to more homogeneous Li depth profiles.

Electrochemical characteristics of ordered mesoporous carbon used as electrode material in Li-ion battery

Ordered mesoporous carbon CMK-5 was comprehensively tested for the first time as electrode materials in lithium ion battery. The surface morphology, pore structure and crystal structure were investigated by Scanning Electronic Microscopy (SEM), N-2 adsorption technique and X-ray diffraction (XRD) respectively. Electrochemical properties of CMK-5 were studied by galvanostatic cycling and cyclic voltammetry, and compared with conventional anode material graphite. Results showed that the reversible capacity of CMK-5 was 525 mAh/g at the third charge-discharge cycle and that CMK-5 was more compatible for quick charge-discharge cycling because of its special mesoporous structure. Of special interest was that the CMK-5 gave no peak on its positive sweep of the cyclic voltammetry, which was different from all the other known anode materials. Besides, X-ray photoelectron spectroscopy (XPS) and XRD were also applied to investigate the charge-discharge characteristics of CMK-5.

Synthesis of ordered nanoporous carbon and its application in Li-ion battery

Ordered nanoporous carbon (ONC) was comprehensively tested for the first time as electrode material in lithium-ion battery. Structure characterization shows the order nanoporous structure and tiny crystallite structure of as-synthesized ONC. The electrochemical properties of this carbon were studied by galvanostatic cycling and cyclic voltammetry. Of special interest is that ONC gave no peak on its positive sweep of the cyclic voltammetry, which was different from other known anode materials. Besides, X-ray photoelectron spectroscopy (XPS) and XRD were also used to investigate the electrochemical characteristics of ONC. (c) 2006 Elsevier Ltd. All rights reserved.

Epitaxial growth of visible to infra-red transparent conducting In2O3 nanodot dispersions and reversible charge storage as a Li-ion battery anode

Unique bimodal distributions of single crystal epitaxially grown In2O3 nanodots on silicon are shown to have excellent IR transparency greater than 87% at IR wavelengths up to 4 μm without sacrificing transparency in the visible region. These broadband antireflective nanodot dispersions are grown using a two-step metal deposition and oxidation by molecular beam epitaxy, and backscattered diffraction confirms a dominant (111) surface orientation. We detail the growth of a bimodal size distribution that facilitates good surface coverage (80%) while allowing a significant reduction in In2O3 refractive index. This unique dispersion offers excellent surface coverage and three-dimensional volumetric expansion compared to a thin film, and a step reduction in refractive index compared to bulk active materials or randomly porous composites, to more closely match the refractive index of an electrolyte, improving transparency. The (111) surface orientation of the nanodots, when fully ripened, allows minimum lattice mismatch strain between the In2O3 and the Si surface. This helps to circumvent potential interfacial weakening caused by volume contraction due to electrochemical reduction to lithium, or expansion during lithiation. Cycling under potentiodynamic conditions shows that the transparent anode of nanodots reversibly alloys lithium with good Coulombic efficiency, buffered by co-insertion into the silicon substrate. These properties could potentially lead to further development of similarly controlled dispersions of a range of other active materials to give transparent battery electrodes or materials capable of non-destructive in situ spectroscopic characterization during charging and discharging.

Assessing charge contribution from thermally treated Ni foam as current collectors for Li-ion batteries

In this report we have investigated the use of Ni foam substrates as anode current collectors for Li-ion batteries. As the majority of reports in the literature focus on hydrothermal formation of materials on Ni foam followed by a high temperature anneal/oxidation step, we probed the fundamental electrochemical responses of as received Ni foam substrates and those subjected to heating at 100°C, 300°C and 450°C. Through cyclic voltammetry and galvanostatic testing, it is shown that the as received and 100°C annealed Ni foam show negligible electrochemical activity. However, Ni foams heated to higher temperature showed substantial electrochemical contributions which may lead to inflated capacities and incorrect interpretations of CV responses for samples subjected to high temperature anneals. XRD, XPS and SEM analyses clearly illustrate that the formation of electrochemically active NiO nanoparticles on the surface of the foam is responsible for this behavior. To further investigate the contribution of the oxidized Ni foam to the overall electrochemical response, we formed Co3O4 nanoflowers directly on Ni foam at 450°C and showed that the resulting electrochemical response was dominated by NiO after the first 10 charge/discharge cycles. This report highlights the importance of assessing current collector activity for active materials grown on transition metal foam current collectors for Li-ion applications.

The structural conversion from α-AgVO3 to β-AgVO3: Ag nanoparticle decorated nanowires with application as cathode materials for Li-ion batteries

The majority of electrode materials in batteries and related electrochemical energy storage devices are fashioned into slurries via the addition of a conductive additive and a binder. However, aggregation of smaller diameter nanoparticles in current generation electrode compositions can result in non-homogeneous active materials. Inconsistent slurry formulation may lead to inconsistent electrical conductivity throughout the material, local variations in electrochemical response, and the overall cell performance. Here we demonstrate the hydrothermal preparation of Ag nanoparticle (NP) decorated α-AgVO3 nanowires (NWs) and their conversion to tunnel structured β-AgVO3 NWs by annealing to form a uniform blend of intercalation materials that are well connected electrically. The synthesis of nanostructures with chemically bound conductive nanoparticles is an elegant means to overcome the intrinsic issues associated with electrode slurry production, as wire-to-wire conductive pathways are formed within the overall electrode active mass of NWs. The conversion from α-AgVO3 to β-AgVO3 is explained in detail through a comprehensive structural characterization. Meticulous EELS analysis of β-AgVO3 NWs offers insight into the true β-AgVO3 structure and how the annealing process facilitates a higher surface coverage of Ag NPs directly from ionic Ag content within the α-AgVO3 NWs. Variations in vanadium oxidation state across the surface of the nanowires indicate that the β-AgVO3 NWs have a core–shell oxidation state structure, and that the vanadium oxidation state under the Ag NP confirms a chemically bound NP from reduction of diffused ionic silver from the α-AgVO3 NWs core material. Electrochemical comparison of α-AgVO3 and β-AgVO3 NWs confirms that β-AgVO3 offers improved electrochemical performance. An ex situ structural characterization of β-AgVO3 NWs after the first galvanostatic discharge and charge offers new insight into the Li+ reaction mechanism for β-AgVO3. Ag+ between the van der Waals layers of the vanadium oxide is reduced during discharge and deposited as metallic Ag, the vacant sites are then occupied by Li+.

Effect of the Electrolyte Formulation on the Performances of Edlc and Li-Ion Batteries

One of the most important components in electrochemical storage devices (batteries and supercapacitors) is undoubtedly the electrolyte. The basic function of any electrolyte in these systems is the transport of ions between the positive and negative electrodes. In addition, electrochemical reactions occurring at each electrode/electrolyte interface are the origin of the current generated by storage devices. In other words, performances (capacity, power, efficiency and energy) of electrochemical storage devices are strongly related to the electrolyte properties, as well as, to the affinity for the electrolyte to selected electrode materials. Indeed, the formulation of electrolyte presenting good properties, such as high ionic conductivity and low viscosity, is then required to enhance the charge transfer reaction at electrode/electrolyte interface (e.g. charge accumulation in the case of Electrochemical Double Layer Capacitor, EDLC). For practical and safety considerations, the formulation of novel electrolytes presenting a low vapor pressure, a large liquid range temperature, a good thermal and chemical stabilities is also required.

This lecture will be focused on the effect of the electrolyte formulation on the performances of electrochemical storage devices (Li-ion batteries and supercapacitors). During which, a summary of the physical, thermal and electrochemical data obtained by our group, recently, on the formulation of novel electrolyte-based on the mixture of an ionic liquid (such as EmimNTf2 and Pyr14NTf2) and carbonate or dinitrile solvents will be presented and commented. The impact of the electrolyte formulation on the storage performances of EDLC and Li-ion batteries will be also discussed to further understand the relationship between electrolyte formulation and electrochemical performances. This talk will also be an opportunity to further discuss around the effects of additives (SEI builder: fluoroethylene carbonate and vinylene carbonate), ionic liquids, structure and nature of lithium salt (LiTFSI vs LiPF6) on the cyclability of negative electrode to then enhance the electrolyte formulation. For that, our recent results on TiSnSb and graphite negative electrodes will be presented and discussed, for example 1,2.

1-C. Marino, A. Darwiche1, N. Dupré, H.A. Wilhelm, B. Lestriez, H. Martinez, R. Dedryvère, W. Zhang, F. Ghamouss, D. Lemordant, L. Monconduit “ Study of the Electrode/Electrolyte Interface on Cycling of a Conversion Type Electrode Material in Li Batteries” J. Phys.chem. C, 2013, 117, 19302-19313

2- Mouad Dahbi, Fouad Ghamouss, Mérièm Anouti, Daniel Lemordant, François Tran-Van “Electrochemical lithiation and compatibility of graphite anode using glutaronitrile/dimethyl carbonate mixtures containing LiTFSI as electrolyte” 2013, 43, 4, 375-385.