FRLP - I+D+i - CENTROS - CITEMA - PUBLICACIONES EN REUNIONES CIENTÍFICAS Y TÉCNICAS
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Item Synthesis and electrochemical properties of Nickel oxide as anode for Lithium ion batteries(Topical Meeting of the International Society of Electrochemistry, 2017-03-19) Ortiz, Mariela; Visintin, Arnaldo; Real, SilviaTransition-metal oxides (MO, where M is Fe, Ni, Co and Cu) have been studied since these materials were proposed by Tarascon and co-workers [1-6]. These oxides can offer higher capacities (600-1000 mAh g-1) that graphite material (372 mAh g-1); in particular, NiO has high theoretical capacity values (718 mA h g-1 for 2Li+per NiO) also present many advantages such as natural abundance, low cost and environmental friendless In this contribution we would like to present the preparation and characterization of nickel oxide as anodes materials in lithium-ion batteries. Two processes are involved in the synthetic procedure; in the first step the nickel hydroxide was obtained by hydrothermal synthesis (4h, 180°C) and then the precipitated was washed with distilled water to remove the residual species. The second step consists of the material calcinations in air at 300ºC, for 4 (NiO-4h) and 24(NiO-24h) hours. The structural characteristics and electrochemical properties of the obtained nickel oxides are subsequently investigated by optical and electrochemical techniques such as: FTIR, SEM, chargedischarge cycles, galvanostatic discharge at different currents, cyclic voltammetry and electrochemical impedance spectroscopy.Item Study of the electrochemical behavior of different carbon materials as anode material for lithium ion batteries(Topical Meeting of the International Society of Electrochemistry, 2017-03-19) Ortiz, Mariela; Visintin, Arnaldo; Real, SilviaSince the lithium ion battery was first commercialized by the Sony Corporation in 1991, the development for improvement it is critical for advancements in a variety of applications ranging from hybrid electric vehicles to consumer electronic [1]. Most lithium ion commercial battery use LiCoO2, LiNiO2 or LiFePO4 as cathode material, organic solvent as the electrolyte and carbon composites as anode material [1-2]. The electrochemical reactions involve Li transfer and exchange of electron. A number of studies have so far been performed for providing a high performance carbonaceous material for the anode of Li-ion batteries [3]. In this study, out of the many available carbonaceous materials we have selected some of them to prepared anodes material and study their electrochemical behavior and correlation to their physical, chemical and physic-chemical parameters.Item Electrochemical performance of Carbon Sulfur as Lithium Sulfur battery cathodes(Topical Meeting of the International Society of Electrochemistry, 2017-03-19) Ortiz, Mariela; Visintin, Arnaldo; Real, SilviaNowadays, rechargeable batteries with higher energy density are required for our society due to the needs of cleaner and more efficient energy systems and with the objective of supplying the increasing technological demands. Commercial lithium batteries are systems based on intercalation compounds able to delivering specific energies about 150-200 WhKg-1, one-third of their theoretical energy ( ≈ 600 Wh kg-1). It is difficult for the reversible capacity of these intercalation compounds to be increased, thus the need to explore new cathodes formed by lighter materials and involving electrochemical reactions of more than one electron. An element satisfying these conditions is sulfur (with a theoretical capacity of 1675 mAhg-1 and a specific energy of 2600 WhKg-1). The lithium-sulfur battery has been investigated by different groups in past decades; however, there are serious drawbacks, which have not been overcome yet, so it limits the practical development of this system [3]. Moreover, sulfur is much more abundant, inexpensive, and non-toxic compared to the transition-metal oxide cathodes. We present here the preparation of composites with carbon and sulfur materials in a single fabrication process: using S2C as the solvent. The characterization of the prepared material was performed using optical techniques (X-ray diffraction, scanning electron microscopy and transmission) and its electrochemical performance in lithium-sulfur batteries was studied using electrochemical techniques such as: charge-discharge cycles, galvanostatic discharges to different currents and cyclic voltammetry. The prepared composite materials delivered higher capacities in the first cycles (≈800 mAhg-1) and then it were stabilized at values around 60% of the initial capacity. Also, carbon electrochemical response was not observed, so its main function is to act effectively as an electron-conducting and support matrix.Item Obtención y caracterización de Li(Ni1/3Co1/3Mn1/3)O2, material de cátodo en baterías de ion litio(JONICER, 2017-10-09) Gamba, Martina; Ortiz, Mariela; Suárez, Gustavo; Real, SilviaArgentina, junto con Bolivia y Chile conforman lo que se ha denominado el “Triángulo del litio”, concentrando entre los tres países el 55% de las reservas mundiales de litio y cerca del 85% de los depósitos de salmueras. El litio es un elemento fundamental en los sistemas de almacenamiento de energía actuales: las baterías de ion-litio están presentes en teléfonos celulares, computadoras laptop, cámaras fotográficas, en sistemas de transporte “verdes” como los vehículos eléctricos (VE) y VE híbridos. Un componente clave que limita el rendimiento de baterías es el material de intercalación del cátodo. Aunque existe gran variedad de sistemas, se conoce que la fase Li(Ni1/3Co1/3Mn1/3)O2 tiene una alta capacidad y excelentes características de ciclado y por ello se la utiliza ampliamente a nivel industrial. Existen diversas metodologías de síntesis. Entre ellas la reacción en estado sólido presenta como ventaja a la sencillez y facilidad de escalado.Item Síntesis y estudio electroquímico de materiales de cátodo en baterías de ion litio(Mattear, 2016-10-12) Ortiz, Mariela; Real, SilviaEl mercado de las baterías está dominado por la tecnología de ion-Litio, sistemas electroquímicos que requieren de materiales de intercalación, soportados en estructuras porosas. Su funcionamiento está basado en el proceso de intercalación de cationes Li+ en el ánodo y en el cátodo, este último constituido, por ejemplo, por óxidos mixtos de metales de transición (LiMO2, siendo M: Mn, Co, y/o Ni), fosfatos de hierro y litio (LiFePO4) u otros materiales. Su desempeño favorable está vinculado a la composición de material activo y su relación masa/área interfacial; optimizar estos parámetros en relación a los mecanismos de las reacciones electroquímicas involucradas permitirá desarrollar variables económicas y de funcionamiento en procesos vinculados a la producción de energía.Item Nickel oxide performance as anode material for lithium ion batteries(IWLiME, 2016-11-01) Ortiz, Mariela; Visintin, Arnaldo; Real, SilviaLithium ion batteries, as a rechargeable power source, have attracted much more attention due to their extensive applications in portable electronic devices and electric vehicles. Although most commercial Li-ion batteries use graphite as anode, a variety of materials have been investigated in order to increase the cell capacity, and therefore its specific energy. Some of these materials are transition metal oxides, which are able to store more Li per gram than graphite and to improve their specific capacities. In this respect, special attention has been given to Fe, Co, and Ni based oxides [1-3]. Particularly, NiO is one of the promising anode materials for Li -ion batteries because of its low cost, environmental friendless and high theoretical capacity values (718 mA h g-1 for 2Li+per NiO).Various NiO components with different structures such as mesoporous, nanosheet, networks, nanowall, nanotube and hollow microsphere have been successfully fabricated [4-5]. In this work, the preparation and characterization of nickel oxide as anodes materials in lithium-ion batteries are presented. Two processes are involved in the synthetic procedure; in the first step the nickel hydroxide was obtained by hydrothermal synthesis (4h, 180°C) and then the precipitated was washed with distilled water to remove the residual species. The second step consists of the material calcinations in air at 300ºC, for 4 (NiO-4h) and 24(NiO-24h) hours. The structural characteristics and electrochemical properties of the obtained nickel oxides are subsequently investigated by optical and electrochemical techniques such as: FTIR, SEM, charge-discharge cycles, galvanostatic discharge at different currents and cyclic voltammetry. The anode materials (NiO-4h and NiO-24h) were synthesized via a facile two-step route and exhibit a satisfactory specific capacity, cyclability and rate capability (Figure 1). These results indicate that the studied electrodes could be suitable as anodes in lithium ion batteries applications.Item Síntesis y estudio electroquímico de materiales de cátodo en baterías de ion litio(Congreso Argentino de Fisicoquimica y Química Inorgánica, 2015-04-12) Ortiz, Mariela; Visintin, Arnaldo; Real, SilviaEn este trabajo se presenta la preparación de óxidos mixtos de Li-Ni-Co-Mn por síntesis hidrotermal, que permite obtener materiales altamente homogéneos a través de un proceso sencillo, de bajo costo y empleando bajas temperaturas. En la síntesis se emplean soluciones precursoras que contienen: Co, Ni, Mn; hidróxido de sodio y de litio; las mismas se introducen en un autoclave a 180 ºC y posteriormente, se realiza la combustión del precipitado obtenido en atmósfera de oxígeno. La caracterización del material preparado se realizó empleando técnicas ópticas (difracción de rayos X, microscopía electrónica de barrido y de transmisión). El desempeño electroquímico de estos óxidos mixtos como material activo en cátodos de baterías de ion-Litio se estudió empleando técnicas electroquímicas como: ciclos de carga-descarga, descargas galvanostáticas a diferentes corrientes, voltamperometría cíclica.Item Preparation and characterization of electrode materials in lithium batteries(Electrochemistry from Sensing to Energy Conversion and Storage, 2015) Ortiz, Mariela; Real, Silvia; Visintin, ArnaldoThe lithium batteries are electrochemical systems based on the use of intercalation compounds supported on porous structures. Different materials are used as cathodes: for example, mixed oxides of transition metals (LiMO2, where M: Mn, Co and / or Ni), and carbons materials (commercial carbon and Sungite carbon) are used as anodes. The preparation of anodes and cathodes materials are presented. Optical techniques (as DRX, SEM and TEM) are used to characterize the prepared material. The electrochemical performance are studied by electrochemical techniques: charge-discharge cycles, galvanostatic discharge at different currents and cyclic voltammetry.Item Contribución de diferentes aditivos en el comportamiento electroquímico de electrodos de hidróxido de níquel(Mattear, 2014-05-13) Ortiz, Mariela; Real, Silvia; Castro, Élida BeatrizEl hidróxido de níquel es utilizado como material activo en electrodos positivos de las baterías alcalinas recargables de níquel. La capacidad de estas baterías depende de la capacidad específica del electrodo positivo y la utilización del material activo, por lo que numerosas investigaciones fueron realizadas con el objetivo de optimizar este electrodo. Entre las mejoras propuestas cabe mencionar el aumento de la conductividad y el potencial de evolución de oxígeno, mejorar la eficiencia de la carga y la inhibición del desarrollo de la fase γ–NiOOH. En consecuencia, es necesario incorporar diferentes aditivos al material activo. Los aditivos que más se destacan son: cobalto [1-2], materiales carbonosos [3], calcio [3], zinc [2] y nanomateriales [4]. En este trabajo estudiamos el comportamiento electroquímico del electrodo de hidróxido de níquel con cobalto (incorporado vía electroless) e hidróxido de níquel nanocristalino (agregado por mezcla directa con el material activo).Estos materiales compuestos se utilizaron para preparar dos electrodos que fueron caracterizados mediante técnicas ópticas y electroquímicas.Item Effect of different additives on the electrochemical behaviour of nickel hydroxide electrodes employed in batteries(Annual Meeting of the International Society of Electrochemistry, 2014-08-31) Real, Silvia; Ortiz, Mariela; Castro, Élida BeatrizNickel hydroxide is widely used as the active material in positive electrodes in most nickel-based rechargeable alkaline batteries. The theoretical capacity of nickel hydroxide is 289 mAhg-1. The capacity of these batteries depends on the specific capacity of the positive electrode and the utilization of the active material because of the positive electrode capacity limitation. The poor conductivity of active material requires the addition of some additives to increase conductivity and, additionally, to increase the oxygen evolution potential, the charge efficiency and to inhibit the development of γ-NIOOH phase. Many studies have been published on nickel hydroxide with different additives to obtain optimum performance; for example: cobalt [1-2], carbonaceous materials [3], calcium [3], zinc [2] and nanomaterials [4]. In this work, we have studied the electrochemical behaviour of nickel hydroxide electrodes containing additives as: cobalt (by electroless technique), nanosized Ni(OH)2 (by direct mix with active material) and MWCNTs (incorporated to active material during hydrothermal synthesis). Their electrochemical characterization was investigated by using cyclic voltammetry, charge-discharge cycling, and electrochemical impedance spectroscopy (EIS) techniques. The experimental EIS data are used to identify the model parameters by fitting the theoretical impedance function; this was derived from the physicochemical model based on the theory of porous electrodes with the charge/discharge processes occurring at the active material/electrolyte interface [5]. The results are found to be useful to determine the key factors responsible of the electrochemical performance of nickel hydroxide electrodes.