FRLP - PRODUCCIÓN EN INVESTIGACIÓN, DESARROLLO E INNOVACIÓN

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Author: search.filters.author.Visintin, ArnaldoSubject: search.filters.subject.Lithium

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    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, Silvia
    Nowadays, 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. 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.
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    Preparation and characterization of electrode materials in lithium batteries
    (Electrochemistry from Sensing to Energy Conversion and Storage, 2015) Ortiz, Mariela; Real, Silvia; Visintin, Arnaldo
    The 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.