Recent advances of NASICON-Na3V2(PO4)3 as cathode for sodium-ion batteries: Synthesis, modifications, and perspectives

Polyanion Na3V2(PO4)3 belongs to sodium-ion super conductor (NASICON) materials, and its NASICON framework offers a stable sodium capacity. The open three-dimensional (3D) channels can provide the transfer paths for sodium-ions. Besides, the unique 3D structure is helpful to achieve the high reversibility of charge and discharge processes. As the cathode compounds for sodium-ion batteries (SIBs), Na3V2(PO4)3 materials meet requirements of low cost and high safety. Moreover, Na3V2(PO4)3 materials possess a high voltage platform and have been widely concerned in SIBs. It is deemed that Na3V2(PO4)3 is a promising cathode material for SIBs. However, the low electronic conductivity of Na3V2(PO4)3 materials hampers the rate capability. Herein, the recent researches of Na3V2(PO4)3 are roundly reviewed. Firstly, this paper introduced the structural characteristics of Na3V2(PO4)3 materials. And then synthetic methods were narrated, such as sol-gel, spray-drying, hydrothermal, electrospinning, and solid-state reaction methods. Moreover, the modified researches of Na3V2(PO4)3 were summarized, mainly including carbon coating, nanocrystallization, and ionic doping. Finally, we prospected the future development direction of Na3V2(PO4)3 modification methods, and made a few suggestions.