Browsing by Keyword "X-ray photoelectron spectroscopy"
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Item AC Magnetron Sputtering: An Industrial Approach for High-Voltage and High-Performance Thin-Film Cathodes for Li-Ion Batteries(2021-05-21) Rikarte, Jokin; Madinabeitia, Iñaki; Baraldi, Giorgio; Fernández-Carretero, Francisco José; Bellido-González, Víctor; García-Luis, Alberto; Muñoz-Márquez, Miguel Ángel; Fernández‐Carretero, Francisco José; Bellido‐González, Víctor; García‐Luis, Alberto; Muñoz‐Márquez, Miguel Ángel; TECNOLOGÍAS DE HIDRÓGENOIndustrial-oriented mid-frequency alternating current (MF-AC) magnetron sputtering technique is used to fabricate LiNi0.5Mn1.5O4 high-voltage thin-film cathodes. Films are deposited on bare stainless-steel substrate at room temperature and then annealed to induce crystallization in disordered spinel phase. In situ X-ray diffraction is used to follow film structural evolution from room temperature to 900 °C. Scanning electron microscopy, X-ray photoelectron spectroscopy, and Raman spectroscopy are used to study the evolution with temperature of film morphology, surface chemical composition, and crystal structure arrangement, respectively. Film structure evolves almost continuously in the studied temperature range. A pattern corresponding to spinel phase is observed after annealing at 600 °C, while poor crystallization is obtained for lower temperatures, and additional unwanted phase changes are observed for higher temperatures. Cyclic voltammetry, rate capability, and cycling performance of fabricated films are tested. Only the film annealed at 600 °C shows redox peaks corresponding to Ni oxidation from 2+ to 3+ and 3+ to 4+ oxidation states, confirming that this film crystallizes in disordered spinel phase. The thin-film cathode shows good rate performance and outstanding cyclability, despite the impurities formed upon electrolyte decomposition at high voltage.Item Characterization of nanostructured Ti–B–(N) coatings produced by direct current magnetron sputtering(2007-02-26) López-Cartes, C.; Martínez-Martínez, D.; Sánchez-López, J.C.; Fernández, A.; García-Luis, A.; Brizuela, Marta; Onate, J.I.; TECNOLOGÍAS DE HIDRÓGENO; INGENIERÍA DE SUPERFICIES; Tecnalia Research & InnovationA series of Ti–B–(N) coatings prepared by dc magnetron sputtering using TiB2 targets in Ar/N2 gas mixtures has been chemically and structurally characterized by transmission electron microscopy, X-ray diffraction, electron energy-loss spectroscopy, and X-ray photoelectron spectroscopy. The influence of synthesis parameters such as applied heating power and nitrogen flow on the structure and chemical composition of the coatings has been studied. Independently of the experimental conditions employed during the synthesis, hexagonal TiB2 is the main crystalline phase present in the coatings. The use of N2 leads to the formation of an amorphous mixture of BN/TiN phases, as well as a diminution of the TiB2 crystalline phase. The influence of the composition and structure of the coatings on their hardness is also discussed.