Browsing by Author "Fernandez, Juan"

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    Determination of the Conformational Preference of para-Aminobenzoic Acid on Vanadium Pentoxide Surface: An XPS and DFT Study
    (2021) Dietrich, Fabian; Fernandez, Juan; Hevia, Samuel; Cisternas, Eduardo; Flores, Marcos
    Self-assembled monolayers are a promising opportunity to control the electrochemical reactions taking place on electrodes of lithium-ion batteries. Such control is relevant to diminish the aging process and to improve the performance of these energy storage devices. From this point of view, the adsorption of para-aminobenzoic acid on vanadium pentoxide, an attractive high-capacity cathode material, is investigated with the combination of experimental angle-resolved X-ray photoelectron spectroscopy as well as dispersion-corrected density functional calculations. Our results show that the molecules prefer a lyingdown or up-standing configuration depending on their concentration. The comparison between experiment and simulation indicates a high coverage of the surface and hence the formation of a self-assembled monolayer of up-standing molecules.
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    In-situ hydrogenated V2O5 thin films: Study of the structural dynamics and their behavior as Li-ion batteries cathode
    (2024) Briceno, Mackarena; Villarroel, Roberto; Zambrano-Mera, Dario; Fernandez, Juan; Flores, Marcos; Rojas-Saez, Nicols; Lisoni, Judit; Hevia, Samuel; Espinoza-Gonzalez, Rodrigo
    This investigation focuses on a one-step preparation method to produce hydrogenated V2O5 thin films by controlling the atmosphere of the DC reactive magnetron sputtering process. An increasing hydrogen flux during the film deposition promotes the formation of defects such as oxygen vacancies and hydroxyl sites in the oxide matrix. The hydrogenated samples were tested as cathodes in Li-ion batteries and exhibited lower charge capacities but superior stability to cycling compared to pristine V2O5 film. These results pave the way to prepare hydrogenated transition metal oxide thin films by a simple route without further thermal procedures and affordable conditions.