Microstructural optimization of glass ceramics LCGTP system

• Grant number: 16/19353-9
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: November 01, 2016
• End date: October 31, 2017
• Field of knowledge: Engineering - Materials and Metallurgical Engineering - Nonmetallic Materials
• Principal Investigator: Ana Candida Martins Rodrigues
• Grantee: Laura Emi Tavoni Mathias
• Host Institution: Centro de Ciências Exatas e de Tecnologia (CCET). Universidade Federal de São Carlos (UFSCAR). São Carlos , SP, Brazil
• Associated research grant: 13/07793-6 - CEPIV - Center for Teaching, Research and Innovation in Glass, AP.CEPID

Abstract

The development of batteries was extremely important to the advancement of electronics, communication and information industry. However, to increase its performance, properties like storage capacity and cyclability should be improved. The electrolytes are essential components of batteries and have substantial influence on their lifetime. Solid electrolytes present advantages over the liquid ones, like the lack of leakages. Among the solid electrolytes, the ones with the NASICON crystalline structure are well known for being good ionic conductors, they reach up to 10-3S.cm-1 at room temperature. In our previous study, glass-ceramics of LCGTP system, with the chemical formula given by Li1+x Crx (Ge0,5 Ti0,5)2-x (PO4)3 0,2d x d 0,8, showed ionic conductivity higher than 10-4 S.cm-1 at room temperature. Besides, we conclude that the addition of Cr and the increase of the heat treatment temperature have a beneficial influence on the ionic conductivity of those electrolytes. However, it was not possible to separate the grain and grain boundary contributions and we have not established in detail the relationship between structural/microstructural characteristics and the ionic conductivity. Therefore, the main goal of this scientific research is to separate grain and grain boundary contribution of the total conductivity, in order to establish correlations between the structure/microstructure and the ionic conductivity of this glass-ceramic and bring new perspectives for the development and optimization of these materials. For this purpose, it will be used the impedance spectroscopy technique (IS) on a wide range of temperatures, including temperatures below the room temperature. Thus, it will be possible to separate and identify the contributions related to the grain and the grain boundary to the total conductivity. These results will be related with the XRD and SEM results, that are techniques used to identify and analyze the phases, structure and microstructure of the glass ceramic. (AU)