A correlative study on electrochemical and optical properties of LLZO (Li7La3Zr2O12) garnet electrolyte

Abstract

The demand for alternative power sources for perceiving sustainable/clean energy has created an increasing interest and becoming more critical owing to the development of applications such as electric vehicles and new type of portable electronic devices currently available in the market. In this regard, relatively safe nature of all solid state batteries (ASSB) makes it distinct as a viable battery over the battery research scenario. Improvement of the technology predominantly depends on the solid electrolyte material employed in the batteries. A very good solid electrolyte must have high ionic conductivity as well as a wide electrochemical window. Lithium Lanthanum Zirconate (LLZO) is one of the promising electrolyte materials for All Solid State Batteries (ASSB). In the present work, LLZO powders have been prepared via a solution route synthesis. The morphology and the purity of the samples were analysed using X-ray Diffraction (XRD), Field Emission Scanning Electron Microscopy (FESEM) and Energy Dispersive X-ray Spectroscopy (EDS) analysis (EIS). The ionic conductivities of the samples were investigated using alternating current Electrochemical Impedance Spectroscopy. UV–vis Spectroscopy was employed to determine the optical band gap of LLZO, and the value (∼6 V) was in agreement with the potential window of LLZO available in the literature. The high potential window and good ionic conducting properties shows that LLZO is a better alternative electrolyte material for next generation solid-state assemblies.