Electrochemical and Thermal Properties of NASICON Structured Na3V2(PO4)3as a Sodium Rechargeable Battery Cathode: A Combined Experimental and Theoretical Study

A combined experimental and computational study on Na3V2(PO4)3 has been carried out to investigate its structural, electrochemical, and thermal properties as a sodium battery cathode. The synthesized material by a sol-gel process was well-indexed to the R-3m space group in the framework of a rhombohedral NASICON structure. Galvanostatic measurements indicate that at 3.4 V vs. Na/Na+, 1.4 Na reversibly reacts with each Na3V2(PO4)3, which corresponds to a specific capacity of 84.8 mAh/g. Moreover, this material shows excellent rate capabilities and good cycling performance. Ex-situ XRD analyzes indicate that this material reacts with Na ions based on a reversible two-phase reaction. Thermal analyzes employing TGA/DSC and In-situ XRD at various temperatures show that this material maintains good thermal stability up to 450°C even in the desodiated state. The promising electrochemical and thermal properties suggest that this material with the well-defined NASICON structure is a promising cathode for large-scale sodium rechargeable batteries.