Estudio de composites catódicos y anódicos activos para baterías de ión litio basados en óxidos y fosfatos de metales de transición

Resumen

Due to the growing interest in the development of new lithium ion batteries with higher energy density and safer operation at lower costs, the exploring of new electrode materials able to fulfill these requirements is still a major challenge.In the present work two cathodic (LiMn2O4 y LiMnPO4) and two anodic (Fe2O3 y NiO) electrode materials have been studied. In order to improve their electrochemical properties three strategies have been employed in the synthesis of these materials: nanostructuration, insertion of small amounts of other elements and the formation of composite materials. Freeze-drying ,as an effective synthetic method to obtain nanostructured materials, has been used in the preparation of all the samples described in this study.In the case of LiMn2O4, the effect of the insertion of Ga(III) and Si(IV) cations on the material properties has been studied. Moreover, in order to minimize the amount of the active material-electrolyte interface, different composite materials have been prepared. For the LiMnPO4 active material, several substitutions with different transition metals (Fe, Co, Ni y Cu) have been carried out as well as coating each sample with in situ generated amorphous carbon. With respect to Fe2O3 and NiO conversion anodes, nanoparticulated carbon composites have been synthesized. In all the cases, structural, morphologic, physico-chemical and electrochemical characterization of the samples have been performed. An enhanced electrochemical performance has been observed in the phases with the particles enclosed in the in situ generated amorphous carbon matrix.Finally, the electrochemical performance