Synthesis and Characterization of the New Li_1+xAl_1+xSi_1–xO₄ (x = 0–0.25) Solid Electrolyte for Lithium-Ion Batteries

A systematic study was performed to investigate the effect of the sintering temperature, sintering duration, and aluminum doping on the crystalline structure and ionic conductivity of the Li_1+xAl_1+xSi_1–xO₄ (LASO; x = 0–0.25) solid electrolyte. There was a strong indication that an increase in the sintering temperature and sintering time increased the ionic conductivity of the electrolyte. In particular, the doping concentration and composition ratio (Li_1+xAl_1+xSi_1–xO₄; x = 0–0.25) were found to be crucial factors for achieving high ionic conductivity. The sintering time of 18 h and lithium concentration influenced the lattice parameters of the LASO electrolyte, resulting in a significant improvement in ionic conductivity from 2.11 × 10^–6 (for pristine LASO) to 1.07 × 10^–5 S cm^–1. An increase in the lithium concentration affected the stoichiometry, and it facilitated a smoother Li-ion transfer process since lithium served as an ion-conducting bridge between LASO grains.