Effect of Multi-step Sintering on the density of Li7La3Zr1.75Ce0.25O12 as Solid State Electrolyte Material

The development of garnets structured lithium lanthanum zirconate, Li7La3Zr2O12 (LLZO) have many amicable characteristics such as high stability against lithium metal anode and wide electrochemical voltage window that make them good solid electrolytic materials for lithium -ion batteries. However, the poor interfacial properties and limited ionic conductivity continue to limit their wide range of applications. Hence, the current study has been focused on improving their ionic conductivity as well as the dense microstructure. This study demonstrates a simple and efficient method to produce compact ceramics with high Li+ conductivity using a multi -step sintering process and variation in grain growth, relative density with the temperature and time variation has been studied. Therefore, garnet -structured oxides with the nominal chemical formula: Li7La3Zr1.75Ce0.25O12 (LLZCO) have been synthesized. TGA, XRD and SEM characterization has been performed to see optimum calcination temperature, phase formation and microstructural analysis of the sample, respectively. The average crystallite size of the prepared LLZCO is estimated about 100 nm as calculated by Scherrer's formula from intense peaks of XRD pattern. Further, the ionic conductivity, electronic conductivities, activation energies along with the electrochemical voltage window stability have been explored.