Synthesis of sio2 nanowires via vapor-liquid-solid (vls) method for their application in li-ion batteries

• Autores: Arancha Gómez
• Directores de la Tesis: Carmen Morant Zacarés (dir. tes.)
• Lectura: En la Universidad Autónoma de Madrid ( España ) en 2016
• Idioma: español
• Tribunal Calificador de la Tesis: Marta Clement Lorenzo (presid.), Julio Gómez Herrero (secret.), Olga Sánchez Garrido (voc.), María del Carmen Cotto Maldonado (voc.), José Manuel Amarilla Álvarez (voc.)
• Programa de doctorado: Programa de Doctorado en Materiales Avanzados y Nanotecnología por la Universidad Autónoma de Madrid
• Materias:
  • Física
    • Electrónica
      • Microscopia electrónica
    • Química física
      • Catálisis
      • Equilibrio químico y de fase
      • Electroquímica
    • Física del estado sólido
    • Física teórica
• Enlaces
  • Tesis en acceso abierto en: Biblos-e Archivo
• Resumen

  • Silica nanowires (SiO2NWs) have attracted considerable attention over the last decades due to their diverse properties and broad range of applications. Among them, it is well-known their capacity to emit strong blue light as well as their versatility as biosensor, since silica can be easily functionalized in order to respond to several targets. Other less-known applications include their potential use in energy conversion, storage devices, field effect transistors or gas sensors. In particular, the present study aims at exploring the suitability of the SiO2NWs as anode in Li-ion batteries. To this end, an extensive work was carried out in order to get SiO2NWs grow via a vapor-liquid-solid (VLS) method, on conductive substrate instead of conventional Si substrates. Accordingly, this study can be divided into two sequential sections.

    In the first part, an in-depth study of the SiO2NWs synthesis is carried out in order to understand the mechanism of SiO2NWs growth as well as the role of the different elements involved in the process. Based on these results, a variety of intermediate elements are assessed as new support-materials for the SiO2NWs growth, among them: titanium nitride (TiN) coatings, carbon nanofibers and silica and carbon microspheres. Finally, a new configuration is designed, in which the Si source is separated from the sample. In this way, SiO2NWs are successfully grown using stainless steel and Cu foils as substrates.

    In the second part, an extensive study of the electrochemical response of the SiO2NWs directly grown on Cu foils was performed in a half-cell configuration. This study comprises galvanostatic cycling, cyclic voltammetry and electrochemical impedance spectroscopy. Likewise, Cu foils of two different thicknesses are also evaluated as current collectors.