Síntesis, caracterización y aplicación de nanocompositos de Óxido de Manganeso de Litio espinela/laminar para la recuperación de litio desde soluciones acuosas

• Autores: Ruth Pulido Venegas
• Directores de la Tesis: Miguel Manso Silván (dir. tes.), Teófilo Graber Seguel (dir. tes.)
• Lectura: En la Universidad Autónoma de Madrid ( España ) en 2022
• Idioma: español
• Número de páginas: 124
• Títulos paralelos:
  • Synthesis, characterisation and application of spinel/layered Lithium Manganese Oxide (LMO) nanocomposites for the lithium recovery from aqueous solutions
• Enlaces
  • Tesis en acceso abierto en: Biblos-e Archivo
• Resumen

  • The growing demand for portable electronic devices and batteries has led to an increasing interest in lithium-based compounds. The traditional process of extracting lithium from brines requires a high rate of water evaporation, which takes months of evaporation and intensive use of reagents to purify the brines due to the presence of numerous ions. Given the constraints of the current lithium recovery process, new technologies have been proposed, among which the application of lithium ionic sieves based on lithium manganese oxides (LMO) elicits as one of the most promising. In this context, this thesis focuses on the synthesis, characterisation and application of spinel/layered type LMO nanocomposites for the recovery of lithium from aqueous solutions. This involves determining the efficiency of these materials in lithium adsorption and desorption processes, along with finding the best laboratory-level operating conditions for efficient operation. First, the effect of crystallisation temperature on the synthesis of LMO nanocomposites by the hydrothermal method was investigated. Here, it was demonstrated that LMO with a high Li/Mn ratio can be formed by systematically favouring the lithium-rich monoclinic layered phase (Li2MnO3) in a mixture of layered and spinel crystalline phases. This synthesis uses the same Li and Mn precursor compounds at slightly different crystallisation temperatures. Furthermore, we report the successful application of the layered phase Li2MnO3 in LMO nanocomposites as lithium adsorbing materials from aqueous solutions, not previously reported. Subsequently, due to the limited information available and the importance of obtaining knowledge of the vibrational properties of the layered phase Li2MnO3, a study based on firstprinciples calculations was carried out. Simulations of the phonon structure and IR/Raman spectra were studied. The results showed the main vibrational modes for the Li2MnO3 structure and IR/Raman simulations in good agreement with the experimental data. These findings helped to understand the underlying mechanisms of lithium ad/desorption from layered-type LMO. Finally, we investigated the lithium desorption behaviour of different LMO nanocomposites in acidic media. The results reported that there is a differential lithium desorption behaviour depending on the Li/Mn ratio of the LMO nanocomposite, with the temperature being the driving force for the success of the desorption process of the lithium-rich nanocomposites. Using a DFT-assisted computational approach, it was shown that the diffusion energy barrier can explain these differences. The experimental and theoretical results conclusively indicate that the lithium desorption process in acidic media is easier to achieve for the LMO spinel crystalline phase than for the LMO layered phase