The safety and stability concerns of liquid electrolytes in conventional lithium-ion batteries have accelerated the development of solid-state alternatives. NASICON type ceramics Li1.5Al0.5Ti1.5(PO4)3 (LATP) offer promising properties, including high bulk ionic conductivity and good compatibility with lithium anodes. However, their practical application is hindered by grain boundary resistance and relatively low total ionic conductivity. This study investigates the effect of Ta2O5 doping on LATP to overcome these limitations. Doping with 5 wt% Ta2O5 improved the ionic conductivity to 2.95 × 10-4 S/cm by enhancing lattice structure, reducing grain boundary resistance, and suppressing the formation of secondary phase. Additionally, Ta2O5 positively influenced the sintering behavior, resulting in a denser, and more uniform microstructure. These enhancements suggest that Ta2O5-doped LATP is a strong candidate for next-generation all-solid-state lithium-ion batteries.
