A comprehensive review on the fabrication, modification and applications of Na3V2(PO4)2F3 cathodes

Abstract

Na-ion batteries (SIBs) have garnered tremendous interest due to their unique advantages of high safety, abundant Na resources, and low cost. Great research efforts of SIBs have been devoted to the exploitation and in-depth mechanism investigation of high-performance electrode materials. Among the various cathodes, Na₃V₂(PO₄)₂F₃ (NVPF), a representative member of Na superionic conductor (NASICON) structured compounds, has been considered to be a promising candidate because of its superior structural stability, fast ion transport, high operating potential and so on. However, its electrochemical performance and future large-scale applications have been hindered by the relatively low electronic conductivity and high cost of NVPF. This review emphasizes the crystal structure and Na storage mechanisms together with synthetic methods of NVPF, and then summarizes various proposed strategies including carbon coating, element doping, size and morphology design, etc. to meliorate the electrochemical performance of NVPF. Additionally, the applications of the NVPF cathode in other battery systems are included. Finally, our perspectives on the subsequent research and optimization of NVPF are also shared. This review not only is a comprehensive summary of NVPF for the first time but also provides a good reference for the rational design of high-performance NVPF in the future.