The growing demand for sustainable and cost-effective energy storage systems has accelerated research into sodium-ion batteries (SIBs) as viable alternatives to lithium-ion technology. This study focuses on the synthesis and characterization of NASICON-type (Na₃Zr₂Si₂PO₁₂, NZSP) solid-state electrolytes, known for their high ionic conductivity and structural stability. Using a solid-state reaction method, two sets of NZSP samples were synthesized from different precursor sources: high-purity-grade chemicals (Sample-A) and more economical but low-purity-grade chemicals (Sample-B). X-ray diffraction (XRD) analysis confirmed successful phase formation in both cases, although a secondary phase structure was found in NZSP based on sample-B; however, the high-purity sample-A showed higher phase purity and crystallinity. Electrochemical impedance spectroscopy (EIS) analysis showed significantly improved ionic conductivity and reduced grain boundary resistance in the sample-A-based NZSP, while sample-B-based NZSP exhibited increased porosity and higher impedance. These differences are attributed to impurity levels and compositional uniformity in the starting materials. The study demonstrates that precursor quality plays a critical role in determining the electrochemical performance of NASICON electrolytes. Although low-purity (Sample-B)-based chemical sources offer a lower-cost pathway, their impact on structural integrity and conductivity must be addressed for practical application. This research highlights the importance of precursor selection in the scalable development of high-performance solid-state electrolytes for sodium-ion batteries, and contributes toward the realization of safer and more efficient energy storage technologies.