Novel NASICON-Type Na-V-Mn-Ni-Containing Cathodes for High-Rate and Long-Life SIBs.

Area of Science:

• Materials Science
• Electrochemistry
• Solid-State Chemistry

Background:

• Sodium-ion batteries (SIBs) are promising energy storage solutions.
• Optimizing cathode materials is crucial for SIB performance.
• Partial substitution of transition metals in Na3V2(PO4)3 (NVP) can enhance electrochemical properties.

Purpose of the Study:

• To synthesize and characterize novel NASICON-type phosphate composites.
• To investigate the effect of Mn/Ni substitution for V on electrochemical performance.
• To elucidate the sodium storage mechanism in the optimized composite.

Main Methods:

• Sol-gel method for composite fabrication.
• Synchrotron-based X-ray studies, XRD, and XPS for structural and chemical analysis.
• Electrochemical techniques including cyclic voltammetry and galvanostatic intermittent titration.

Main Results:

• Successful synthesis of NASICON-type Na-V-Mn-Ni phosphate composites.
• Demonstrated successful substitution of V by Mn/Ni within the crystal structure.
• Identified Na3.83V1.17Mn0.58Ni0.25(PO4)3 (VMN-0.5) as the optimal composition with high capacity (108.1 mAh g-1 at 0.2 C).
• VMN-0.5 exhibited excellent performance in quasi-solid-state sodium metal batteries.

Conclusions:

• Mn/Ni substitution effectively enhances the electrochemical properties of NVP-based NASICON materials.
• VMN-0.5 shows significant potential as a high-performance cathode for SIBs.
• The findings support the commercialization of NASICON-type materials for sodium-ion batteries.