Síntesis y caracterización de materiales nanométricos para su aplicación en baterías recargables de ión litio y plomo-ácido

La Tesis Doctoral "Síntesis y caracterizaicón de materiales nanométricos para su aplicación en baterías recargables de ión-litio y plomo-ácido" se enmarca dentro del creciente interés en la investigación sobre nanomateriales y nanotecnología. En el desarrollo de la memoria se presenta el estudio materiales nanoestructurados para su aplicación en electrodos positivos en las dos tecnologías de acumuladores de mayor mercado mundial. Para el caso de baterías de plomo-ácido, se evalúa la preparación de electrodos delgados a partir de materiales convencionales, comparándose con placas delgadas fabricadas a partir de óxidos de plomo nanocristalinos. El rendimiento electroquímico de las baterías prototipo montadas con estos últimos electrodos revela las buenas propiedades de ciclaje de estos óxidos nanométricos conferidas por su especial morfología. En el apartado e baterías recargables de litio, se ha empleado un método rápido y sencillo para la síntesis de fases laminares [LiCo1-xNixO2 (x=0, 0.5)] y espinelas [LiMn2-xMxO4 (M=Ni, Cu; x=0, 0.5)]. La molienda de oxalatos metálicos hidratados y su posterior calcinamiento conduce a la obtención de partículas nanométricas de alta superficie específica. Estos materiales presentan un comportamiento notable a varias densidades de corriente tanto en celdas de 4V como en baterías de 5V. Este rendimiento puede ser optimizado introduciendo un agente polimérico durante la síntesis de las nanoestructuras, consiguiendo ampliar el rango de velocidades de ciclaje, así como liberar una alta capacidad específica de manera estable

Estudio del hueso de oliva como fuente de carbón para baterías de litio

III Encuentro sobre Nanociencia y Nanotecnología de Investigadores y Tecnólogos Andaluce

Lithium sulfur battery exploiting material design and electrolyte chemistry: 3D graphene framework and diglyme solution

Herein we investigate a lithium sulfur battery suitably combining alternative cathode design and relatively safe, highly conductive electrolyte. The composite cathode is formed by infiltrating sulfur in a N-doped 3D graphene framework prepared by a microwave assisted solvothermal approach, while the electrolyte is obtained by dissolving lithium bis(trifluoromethane)sulfonimide (LiTFSI) in diethylene glycol dimethyl ether (DEGDME), and upgraded by addition of lithium nitrate (LiNO3) as a film forming agent. The particular structure of the composite cathode, studied in this work by employing various techniques, well enhances the lithium-sulfur electrochemical process leading to very stable cycling trend and specific capacity ranging from 1000 mAh g−1 at the highest rate to 1400 mAh g−1 at the lowest one. The low resistance of the electrode/electrolyte interphase, driven by an enhanced electrode design and a suitable electrolyte, is considered one of the main reasons for the high performance which may be of interest for achieving a promising lithium-sulfur battery. Furthermore, the study reveals a key bonus of the cell represented by the low flammability of the diglyme electrolyte, while comparable conductivity and interface resistance, with respect to the most conventional solution used for the lithium sulfur cell

Versatility of a Nitrogen-Containing Monolithic Porous Carbon for Lithium-Based Energy Storage

N-containing monolithic porous carbon material with dual micro and mesoporous structures was synthesized using an innovative, cheap and easy synthesis route based on the classical resorcinol-formaldehyde synthesis. A completely chemical, structural and morphological characterization was carried out. The N content in the carbonaceous material was 7.3 % and XPS data showed that is present in two different surrounds, as N-pyrrolic and N-pyridinic atoms. Is known that, the last one, can acts as a catalyst at surface level in heterogeneous reactions. In addition, using this material, we were able to fabricate lithium-ion and lithium-sulfur batteries obtaining high values of discharge capacity and cycle stability and demonstrating the multifunctional character of this carbon in energy storage devices

Nano-alambres de dioxido de manganeso como material electroactivo en supercondensadores

III Encuentro sobre Nanociencia y Nanotecnología de Investigadores y Tecnólogos Andaluce

Nanomateriales cristalinos como electrodos en bacterías acuosas Li-ión

II Encuentro sobre nanociencia y nanotecnología de investigadores y tecnólogos de la Universidad de Córdoba. NANOUC

Improving the performance of biomass-derived carbons in rechargable lithium batteries

III Encuentro sobre Nanociencia y Nanotecnología de Investigadores y Tecnólogos Andaluce

Biomass-derived carbon/γ-MnO2 nanorods/S composites prepared by facile procedures with improved performance for Li/S batteries

The promising prospects of the Li/S battery, due to its theoretical energy density of about 2500 Wh kg─1, are severely limited by two main weaknesses: the poor conductivity of S and the solubility of the polysulphides in the electrolyte. A combination of carbon and transition metal oxides is the best option for mitigating both of these shortcomings simultaneously. In this work, we use hydrothermally-tailored γ-MnO2 nanorods combined with an activated biomass-derived carbon, which is an inexpensive material and easy to prepare. This strategy was also followed for a AC/MnO2/S composite, a preparation of which was made by grinding; this is the simplest method for practical applications. More complex procedures for the formation of in situ hydrothermal MnO2 nanorods gave similar results to those obtained from grinding. Compared with the AC/S composite, the presence of MnO2 markedly increased the delivered capacity and improved the cycling stability at both low (0.1 C) and high (1 C) currents. This behaviour results from a combination of two main effects: firstly, the MnO2 nanorods increase the electrical conductivity of the electrode, and secondly, the small particle size of the oxide can enhance the chemisorption properties and facilitate a redox reaction with polysulphides, more efficiently blocking their dissolution in the electrolyte