Research Progress on Electrochemical Properties of Na3V2(PO4)3 as Cathode Material for Sodium-Ion Batteries

The polyanion sodium vanadium phosphate Na3V2(PO4)3 (NVP) belongs to the sodium superionic conductors (NASICON) material. Its NASICON structural backbone forms a stable sodium accommodation site, and the open threedimensional ion transport channel is conducive to the rapid intercalation/deintercalation of Na ions. As a cathode material for batteries, Na3V2(PO4)3 has an extremely high specific capacity, voltage plateau, and cycle stability, meeting the requirements of low cost and high safety. It is a large-scale energy storage material with ideal potential and has received extensive attention. However, the low electronic conductivity of Na3V2(PO4)3 material hinders its further application. Based on the current demand for large-scale application of sodium-ion batteries, this paper re-examines the effect of existing research progress on promoting practical applications and the problems that need to be solved in the future from the perspective of raw material cost system and process complexity. The paper first introduces the structural characteristics of Na3V2(PO4)3 material and the mechanism of sodium-ion intercalation/ deintercalation. Then it introduces the synthesis methods, such as the sol-gel method, hydrothermal method, and solid-phase reaction method. In addition, it summarizes the modification studies of Na3V2(PO4)3, including carbon coating, ion doping and, morphology control, design of composite materials and structures based on Na3V2(PO4)3. Finally, it discusses the possible future development of Na3V2(PO4)3.