A Comparative Study of the Structural and Electrochemical Properties of Na 3 V 2 (PO 4 ) 3 /C Cathode Materials for Na‐ion Batteries Prepared by Sol‐Gel vs . Solid‐State Methods

Na‐ion batteries have attracted much attention as one of the most promising alternatives to lithium‐ion batteries. Na 3 V 2 (PO 4 ) 3 has been widely investigated as a cathode material for Na‐ion batteries because of its high structural and thermal stability, leading to high cycling performance and safety. The cathode material also possesses a three‐dimensional open framework and consequently provides high ionic conductivity, as well as high‐rate capability. However, the cathode type experiences poor electronic conductivity, affecting its electrochemical properties. It is well established that preparation methods have remarkable effects on the crystal structure and morphology of electrode materials, altering their electrochemical performance. Thus, this work focuses on a comparative study of the morphology, structures, electrochemical performance, and kinetic properties of Na 3 V 2 (PO 4 ) 3 /C cathodes prepared by sol‐gel and solid‐state methods, which are simple and scalable. The results reveal that sol‐gel and solid‐state reaction processes provide Na 3 V 2 (PO 4 ) 3 /C cathode materials with different structural and morphological characteristics, significantly affecting their electrochemical performance and kinetic properties. This is a crucial key to finding a proper synthesis method to achieve Na 3 V 2 (PO 4 ) 3 /C with high performance for commercial large‐scale production.