▎ 摘　　要

Metallic transition metal selenides are broadly applied in energy storages because of their excellent electroconductivity and high theoretical capacity. However, the poor cycling life which comes from irreversible volume expansion and the formation of soluble selenides intermediates make it hardly use in commercialization. In this work, ultra-fine metallic VSe2 nanoparticles anchored reduced graphene oxide composite (VSe2/rGO) is prepared by an accessible one-step hydrothermal method. The small particle size of VSe2 and the unique structure endows the composite a high specific capacity of 156.8 mA h g(-1) at 1 A g(-1), and maintain 53.2% of original capacity even at 15 A g(-1). In addition, the anchoring effect of the composite process can effectively improve the durability of the VSe2 nanoparticles. Furthermore, an aqueous energy storage system based on the prepared VSe2/rGO cathode and a carbon coated Fe3O4 nanoparticle anode is assembled with considerable energy and power densities. This study sheds lights on the application of metallic VSe2 for high performance cathode materials for energy storage.