With the development of renewable energy sources,emerging energy storage systems have received a lot of attention. Sodium-on batteries have attracted extensive attention in the field of large-scale energy storage due to their abundant sources, safety,low cost,environmental friendliness and ease of use.The cathode materials of sodium-ion batteries affect the key properties of the battery such as energy density,cycling performance and multiplication characteristics.Currently,three cathode materials for sodium ion batteries have entered the industrialization horizon,namely layered transition metal oxides,polyanionic compounds and Prussian blue compounds.This paper summarizes the classification,properties,and research progress of main cathode materials for sodium-ion batteries,and anticipates the prospect of the potential research.

Sodium?ion batteries (SIBs) have the advantages of rich resources and low cost and supply risk.Therefore,they are regarded as a new generation of electrochemical energy storage devices with great potential.At present,vanadium pentoxide (V₂O₅) has gradually become a research hotspot of cathode materials for SIBs because of its high working voltage and theoretical capacity. However,the disadvantages of V₂O₅ cathode material,including low ion diffusion coefficient,low conductivity,and structural instability caused by repeated ion intercalation/deintercalation,have limited its application in SIBs.This paper analyzed the crystal structure and sodium storage mechanism of V₂O₅ and summarized the research progress of V₂O₅ cathode material in SIBs through modification methods such as morphology control,crystal structure modification,chemical pre?insertion,and composition with other materials.Finally,the paper prospected the development trend of V₂O₅ electrode material.