Stability and Scalability of Na₃V₂(PO₄)₃ Cathode Material for Next-Generation Sodium-Ion Batteries

This research focuses on the synthesis and characterization of Na₃V₂(PO₄)₃ (NVP) as a cathode material for sodium-ion battery (SIB). A sol-gel technique was used to synthesize NVP nanoparticles as electrode materials for SIBs. The synthesized materials include pristine NVP-1, a stored sample (NVP-2) to examine time-induced degradation or structural stability, and NVP-3, a bulk sample (10× scale) for large-scale production analysis. The creation of a rhombohedral NASICON-type structure (R3c space group) is confirmed by XRD with minimal lattice distortion. Thermogravimetric analysis (TGA) highlights the material's stability, with weight loss attributed to water evaporation and carbon combustion. Vanadium and phosphate ions' oxidation states are confirmed using X-ray photoelectron spectroscopy (XPS). Surface morphology, analyzed using FE-SEM, reveals nano-sized particles with some agglomeration, influencing electrolyte penetration and ion transport. A comparative analysis of stored and fresh samples reveals subtle structural shifts without phase changes, indicating robust long-term stability. The calculated crystallite size and c/2a ratio align with standard values, reflecting minimal strain and efficient Na⁺ diffusion. This comprehensive study demonstrates that NVP offers excellent phase stability and structural potential, giving it the potential to be used in energy storage systems of the future.