FRECHERO marisa Alejandra
congresos y reuniones científicas
Lithium Glasses. Improvements as a solid electrolyte
FRECHERO M. A.
Simposio; Simposio Internacional. Desafío en las baterías recargables de litio oxígeno; 2012
There is not doubt that, in the last decades, the need for a portable power source has increased due to the miniaturization of electronic appliances. Also, the operation of some diminutive electric devices has been possible thanks to the development of the technology for very little power sources which require, in many cases, low power and because of this, the science of the semiconductor materials has made a remarkable progress. The demand for batteries with high energy densities has inevitably led to the research and development of new electrolytes thermodynamically more stable than aqueous electrolytes. For extreme miniaturization and very simple production the techniques are of obvious importance: performance and reliability are key factors. What technology needs, in general, is an electrolyte with high conductivity at room temperature and a high potential of decomposition to open up a wide range of technological applications. Many compounds have been studied with these goals in mind and many of these materials, in the ionic conductivity field; have the spotlights on the lithium cation. This ion has some very attractive properties as a charge carrier, one can highlight that it is the metallic cation with the lowest atomic weight: solid electrolytes with lithium -as the mobile specie- have high energy densities which allow to develop light and compact batteries with high voltages and low discharge level, which in turn permit to extend the lifetime of an electric device as well. The glassy systems appeared during the second half of the last century as the ideal material in this field. The lithium glasses have many advantages as a solid electrolyte, because they are easy to manufacture, their properties are isotropic and, they have a huge range of possible compositions. But, they still have a moderate conductivity at room temperature. The most common method used to manufacture glasses is ?the quenching?. The thermal history in the manufactured process is relevant to their properties. In the previous context, tellurite glassy systems with lithium cation as a charge carrier are the main objectives in our work. We seek to improve not only the ionic conductivity but also other properties in the glassy matrix, e.g. glass transition temperature, enthalpy of matrix relaxation, etc. In addition, we explore the relationship between the ionic conductivity with the main features of the ?structure? of the glassy matrix at atomic level, short range order and even at intermediate range order. Usually, different techniques are used: FTIR, XRD, DSC, Density, UV-Vis and BDS. We are interested on the comparison of the electrical response between lithium cation with others mobile cations and, in the knowledge of the ?glassy matrix structure? due to that is essential to understand how to control its middle-range order, which is relevant in the electrical conduction processes and, as a consequence, in the technological applications of these materials as solid electrolytes.