A Raman spectroscopy study of tetragonal and cubic lithium garnets

Abstract

Resumen del póster presentado al "31st RSC Solid State Group Christmas Meeting" celebrado en Liverpool (UK) del 19 al 20 de diciembre de 2011.Lithium garnets have been proposed as good candidates for their use as electrolytes in lithium batteries but, however, there is still controversy about the sites occupied by lithium ions in the structure and the mechanisms involved in the conduction process. One of the reasons for these discrepancies is the fact that materials with different properties are obtained depending on the synthesis method, thermal history and storage conditions of the samples. In this context, we use Raman scattering with the hope that a spectroscopic technique might provide a new perspective on the local environment of lithium ions and their diffusion mechanism. Specifically, we have focused on the role of temperature and lithium stoichiometry on the tetragonal to cubic transition in Li7La3Zr2O12 observed at about 150ºC. We have found that this transition is accompanied by the formation of lithium carbonate, indicating a loss of lithium in the garnet phase and leading to some differences between this low temperature cubic phase and that obtained at high temperature. The reversibility of this low temperature phase transformation has also been studied.Peer Reviewe