Conformal Solid State Li₇La₃Zr₂O₁₂–PEO-LiClO₄ Composite Electrolyte for Advanced Lithium Batteries

Lithium Ion Battery (LIB) has dominated the field of energy storage devices due to its high energy density and high power delivery. However, there are major safety concerns associated with organic liquid electrolytes currently used in Li-ion batteries. In order to mitigate the problem, the concept of all solid-state battery has been developed. The application of solid electrolyte in practical cells has been hindered by its high electrode/electrolyte interface impedance and the low ionic conductivity of this class of electrolytes. In this research, we have investigated a garnet type super Li-ion conductor Li₇La₃Zr₂O₁₂ (LLZO) compounded with polyethylene oxide containing LiClO₄ as a solid electrolyte. We have synthesized LLZO with sol-gel method and casted LLZO/PEO-LiClO₄ composite film with ~100 μm thickness with different LLZO concentration (0%-80%). The composite film conductivity was measured using Electrochemical Impedance Spectroscopy (EIS) in the range of 10 mHz to 100 kHz, with Ni blocking electrodes. The electrolyte with 50 w% LLZO content showed higher Li-ion conductivity (~ 10^-6 S/cm) at room temperature compared to other concentrations. Vibrational spectroscopy has been employed to investigate the role of LLZO on polymer crystalline phase.