FAST IONIC CONDUCTOR FOR LITHIUM-ION BATTERY

Abstract

Li –ion battery is one of the most promising primary energy storage units for the portable electronic device as well as it will continue to play an incomparable role in sustainable energy future. But Li ion battery still can’t live up to increasing demand of our society due to the low energy density and safety concern despite the decades of development. There are many complexes are associated with the state of art liquid electrolyte because of its flammability and intrinsic volatility. Solid state ionic conductor has received much attention and represents a promising class of material for the next generation high energy density battery. Garnet type super-ionic conductor has emerged as the potential candidate for solid electrolyte owing to their good chemical and thermal stability as well as high conductivity. This dissertation includes my project work on the synthesis and characterization of novel garnet type solid ionic conductor and their properties and applicability in Li-ion battery. The goal of this M.Tech. dissertation is to develop the garnet structured ionic conductor and to generate fundamental understandings with the doping effect of the Nb and Mn on frame of Li7La3Zr2O12 (LLZO) which has been successfully achieved through solid state (ceramic) method. The garnet-structured Al substituted (LLZO) electrolyte surfaces and interfaces properties and multi doping effect is also included and discussed properly in this thesis. The sample Li7La3Zr2O12 and Li6.25Al0.25La3Zr2O12 are synthesized by solid state reaction as well as have made an attempt to understand the structural properties and morphological studies, thermal and chemical stability as well as conductivity measurement of the synthesized samples. The analysis of material properties as structural characterizations is done by Powder X- Ray diffraction (PXRD) technique and morphological studies with the help of Scanning electron microscopy (SEM). We have done TGA/DTA analysis for thermal stability and EDX for the elemental analysis of LLZO. Further FTIR spectroscopy has been done for identification of bonding in the material. For the confirmation of porous nature as well as pore size and its distribution in the material, we have done the BET surface area analysis and at last for the electronic and ionic conductivity measurement, two probe method and Electrochemical impedance spectroscopy (EIS) is performed.