Study of Mechanism Mobility of Calcium and Magnesium-Doped Lithium-Based Germanium Oxide Electrolytes for Lithium-Ion Batteries

Abstract

In this study, synthesis and characterization of electrolytes containing lithium oxide incorporated by Ge³⁺ with a basic formula of Li_0.8Ge_0.2–xO_1.9 (where x is equal to 0.05, 0.10, 0.15) and doped lithium with Ca²⁺ and Mg²⁺ ions using Li_1−xM_xO_2−δ (M = Ca, Mg) formula were produced through simple and cost-effective co-precipitation method. All the samples exhibited a perfect match with the rhombohedral-type structure, also demonstrating a good crystalline nature were examined using X-ray powder diffraction. The radii of the Li³⁺ (0.76 Å) and Ge³⁺ (0.53 Å) ions are almost close to that of Ca²⁺ and Mg²⁺. Further, structural modifications were investigated through Raman spectroscopy. The measurements recorded within the spectral range of 50 to 1000 cm^–1, offer a comprehensive view of the vibrational characteristics of these materials. Minor functional group modifications were identified by FT-IR analysis. Optical absorption spectra were obtained from LiO₂ electrolyte samples doped with varying concentrations of Ge³⁺, Ca²⁺ and Mg²⁺ ions, covering a wavelength range of 200 to 800 nm. The study utilizes SEM and EDAX to provide an in-depth investigation of the morphology and elemental composition of LiO electrolyte samples co-doped with varying concentrations of Ge³⁺, Ca²⁺ and Mg²⁺ ions. The EDAX spectrum confirms the presence of Li, Ge, Ca, and Mg elements, validating the doping process and ensuring the accuracy of the sample preparation. The role of individual grains and grain boundaries in the overall conductivity was explored through AC impedance spectroscopy, conducted over low temperature range.