A comparative study of LiTa2PO8 ceramics prepared with different lithium sources

Abstract

In advancing lithium-ion batteries, solid electrolytes like LiTa₂PO₈, a Li-ion conductor with high bulk conductivity (~10⁻³ S/cm), show promise for all-solid-state battery technology. Here, we investigate the impact of different Li sources and their excess on the structural, microstructural and electrical properties of LiTa₂PO₈ ceramics. Employing diverse characterization techniques, including XRD, MAS NMR, TMA, SEM/EDS, IS, DC potentiostatic polarization, and density measurements, we unveil significant impact of the source of lithium ions and its excess on electrical properties. The sample without excess LiNO₃ source exhibited the highest σ_tot = 5.2×10⁻⁴ S/cm at 30°C. Notably, the grain conductivity remained constant at ca. 3 mS/cm, irrespective of the chosen lithium source and excess. The microstructural analysis uncovered correlations between variations in total ionic conductivity and changes in the nature and concentration of secondary phases. Additionally, it revealed the influence of the arrangement of grains affecting the grain boundaries and porosity regions.